Non binary cocktail attire

So, I’m a 45 year old non-binary (for wanting a better term) but generally present as white middle aged cis het male. I’ve been doing drag as a DJ and performer for about 15 years. In that time I’ve fathered two kids and the oldest is now 7. I’ve never kept my drag from them - they discovered it themselves through paraphernalia and photos and it’s been somewhat normalised in our household and family. Now, they have started telling friends at school. While I know some of the more liberal parents know and accept and celebrate the fact, I’m worried how far this might reach and it’s impact with the inevitable terf fallout and how this will affect my kid. I don’t know what I’m asking really other than - are there any other more ‘mature’ Kweens out there that might have some advice? Do I quit drag or embrace it as a tool for education?

Obviously a joke cause I'm pretty sure both those planets can't support complex life forms at the moment, but where in the universe would non binary people like to be from?

I am a 16 year old boy who wants to become a transgender woman and crossdress and become a drag queen. I am feeling a lot of gender dysphoria right now, and I don’t like being a man and want to be a girl. I am not wanting to become transgender because I’m homosexual, I am straight and am not a gay man, although I would want to identify as lesbian and femme-sexual when I transition into a woman, I am just not fond of being a man and I want to become a woman. I also really hope that everyone in the LGBTQ community gets treated much better and that the laws and rules that prohibit them from doing what they want such as the bathroom and locker room and the gender separation rules and laws would not be quite so harsh for everyone and would cease to exist so that trans and queer and bisexual and non binary people can live their best lives without having to deal with any rules or peefamily/friend/legal issues and conflicts and laws that stop them from living the happy lives that they want to experience. Y’all should please love and support and fight for LGBTQ people and their rights. WE PEOPLE SHOULD BE EQUAL! 🏳️‍🌈🏳️‍⚧️💕

I am a 16 year old boy who wants to become a transgender woman and crossdress and become a drag queen. I am feeling a lot of gender dysphoria right now, and I don’t like being a man and want to be a girl. I am not wanting to become transgender because I’m homosexual, I am straight and am not a gay man, although I would want to identify as lesbian and femme-sexual when I transition into a woman, I am just not fond of being a man and I want to become a woman. I also really hope that everyone in the LGBTQ community gets treated much better and that the laws and rules that prohibit them from doing what they want such as the bathroom and locker room and the gender separation rules and laws would not be quite so harsh for everyone and would cease to exist so that trans and queer and bisexual and non binary people can live their best lives without having to deal with any rules or peefamily/friend/legal issues and conflicts and laws that stop them from living the happy lives that they want to experience. Y’all should please love and support and fight for LGBTQ people and their rights. WE PEOPLE SHOULD BE EQUAL! 🏳️‍🌈🏳️‍⚧️💕

I am a 16 year old boy who wants to become a transgender woman and crossdress and become a drag queen. I am feeling a lot of gender dysphoria right now, and I don’t like being a man and want to be a girl. I am not wanting to become transgender because I’m homosexual, I am straight and am not a gay man, although I would want to identify as lesbian and femme-sexual when I transition into a woman, I am just not fond of being a man and I want to become a woman. I also really hope that everyone in the LGBTQ community gets treated much better and that the laws and rules that prohibit them from doing what they want such as the bathroom and locker room and the gender separation rules and laws would not be quite so harsh for everyone and would cease to exist so that trans and queer and bisexual and non binary people can live their best lives without having to deal with any rules or peefamily/friend/legal issues and conflicts and laws that stop them from living the happy lives that they want to experience. Y’all should please love and support and fight for LGBTQ people and their rights. WE PEOPLE SHOULD BE EQUAL! 🏳️‍🌈🏳️‍⚧️💕

I am a 16 year old boy who wants to become a transgender woman and crossdress and become a drag queen. I am feeling a lot of gender dysphoria right now, and I don’t like being a man and want to be a girl. I am not wanting to become transgender because I’m homosexual, I am straight and am not a gay man, although I would want to identify as lesbian and femme-sexual when I transition into a woman, I am just not fond of being a man and I want to become a woman. I also really hope that everyone in the LGBTQ community gets treated much better and that the laws and rules that prohibit them from doing what they want such as the bathroom and locker room and the gender separation rules and laws would not be quite so harsh for everyone and would cease to exist so that trans and queer and bisexual and non binary people can live their best lives without having to deal with any rules or peefamily/friend/legal issues and conflicts and laws that stop them from living the happy lives that they want to experience. Y’all should please love and support and fight for LGBTQ people and their rights. WE PEOPLE SHOULD BE EQUAL! 🏳️‍🌈🏳️‍⚧️💕

I seriously hate leaving my house, even as a adult nothing I do to just pass is good enough, I could wear a hoodie,a shirt and my binder and it still wouldn’t be flat enough, I cut my hair as short as I can, down to a buzz cut, I try to lower my voice, I try to change everything I can on my own.. and it’s still not enough.
I’m so used to being misgendered and deadnamed it’s just numbing and exhausting at this point. My mom started asking me a bunch of trans questions today for no reason, (she’s so uneducated so some terms she used alone stung) and she kept asking me questions about me , which I hated..she then asked if people automatically see me as female and if people can even see me as anything but a girl ..and I hated that, because people DO..everyone does, I didn’t even want to answer because ouch that question hit a few nerves..
I may be non binary but I also don’t mind if people see me as a guy.. or at-least don’t automatically see a girl, and it sucks because sometimes I don’t know what I’m doing wrong, or what more I can do on my own,and even if someday I do get too surgery and start T and all that..it probably still won’t be enough

hi there! i’m sam (they/them)! i’m trans non-binary and i just got at date for top surgery! i’m very excited about it, but i wanna make sure i’m asking my surgeon all the right questions to be prepared for surgery and what to expect post op ! i have ideas of what needs to be talked about, but i’d love to hear tips, advice, and stories from the trans community on reddit! thanks for taking the time to scroll through my post; i look forward to reading any and all comments i may get :D

I'll try to keep this short, since I mostly want to vent/ramble. Sorry I'm just going to type and not really go back and make this super coherent.
I'm non-binary, afab, and female presenting. My ex is cis female. We're both in our mid-20s but I consider myself a late bloomer in dating and this was my first serious relationship so I get that this whole situation is gonna feel horrible for me. My ex and I are no contact since November and we both have each other blocked everywhere so there's 0 chance of us seeing anything or messaging. We don't even have friends in common anymore since we were long distance (aside from one or two people but they are distant friends of both of us), and the break occurred right before I was supposed to move in with them. (They had been insistent that I move in because they hated the distance for a while so it was quite the surprise when they said they wanted to break up.) I did some therapy, had to stop because I couldn't afford it after some time. I know moving on from a break up doesn't have real deadlines, but I hate feeling like I make progress and then fall back several steps or even back to step one. Admittedly I had a period where I felt fine and then for the past month it's gotten bad again. I know I deal with some degree of depression and anxiety, but that isn't my first rodeo with those illnesses.
I feel like I messed up somehow and I don't know what and I feel like that makes me horrible for not knowing how what bad thing I had done to cause the break up. The last couple conversations I had with my ex, where I we talked about what went wrong between us, I got some vague reply about something I did post-break-up. But if it happened after I feel like that can't "cause" a break up, so maybe they were trying to save my feelings, which honestly hurts more because I won't be able to improve for the future if I don't know what I had done wrong in the past. Maybe it's a lack of my own self-awareness.
For a while she was adamant about wanting to be my friend post-breakup, enough to message me saying she was sick and taking time off work and wanted to co-op in a game that day. (I declined, it was literally a few days after she said she wanted to break up, like... damn I don't get over things that fast, even if I have the chance of being your friend after.) And then in November I messaged her and was told never to speak to her again. (My friend said she was saying something about our relationship being toxic over social media, screenshots as proof, and I confronted her, because why would I want to be friends with someone who sees me like that.) She said something about how she has done nothing but love me and not to speak to her again so I didn't. Mistake mentioning it at all, I know, but I guess it's cutting off someone that didn't really want me around anyway. My friend kept me posted for a while, she started posting about how she hoped I healed or that she was wishing me well. Eventually I asked for them to stop because I didn't exactly want to keep tabs on how my ex was feeling, I felt shitty enough already and I didn't even want the relationship to end.
TL;DR. Having bad feelings come back (enough to trigger my depression and make me unable to get out of bed and do basic things like eat) despite have little to no reminders of my ex now. (Just intrusive thoughts.) Thought it was over and done with. Frustrated it's taking so long to move on. The end of the relationship was confusing for me. I think I did something wrong but I honestly don't know. I probably just need to accept that the closure just won't ever come, despite asking when we were still on speaking terms.

I know the best people to ask if my insurance and the doctors but I have anxiety so I would love to talk to someone with first hand experience prior to putting myself through that discomfort lol. Any non-binary transmasculine people in here who have opted for a breast reduction instead of double mastectomy?? If so do you know if I could request a breast lift with the reduction. Im worried that the outcome with just make me have small saggy boobs when all I want is small boobs that I can hide easily when I want to and take out when I want to. On a similar not I am considering aspects of facial masculinization surgery mostly just defining my jaw since I have a very small round face but I know rhinoplasty can be a gender affirming surgery with facial masculinization but me being non-binary I would really just like to make my nose a teeny bit smaller at the top. I want to be as androgynous as possible and I feel like the jaw with the nose would help bring balance. I just don’t know if they’ll be like “umm you have to get a man nose to get coverage”. Idk anyone have any thoughts? Also please be kind, I have enough anxiety around all of this already.

Bonne lecture.
Pas à pas Shedet s’enfonce dans la grotte, la corniche qu’il a emprunté fut plus sûre qu’il ne l’espérait. « Je perçois du bruit, il y a quelqu’un ici, enfin je l’espère car si c’est une de ces bêtes féroces je suis foutu ». En avançant en tâtant le mur, la probabilité de trouver une personne s’intensifie tant le bruit est clair. Le faible écho d’un individu s’agitant de manière frénétique. Shedet touche de la main une torche accrochée au mur par un crochet si faible qu’il s’en détache avec l’objet, des gravats lui tombe sur les pieds ensanglantés par la course. Soudain une voix féminine brise le silence:
— Qui va là? Pitié ne me faites pas de mal. Une autre torche s’allume progressivement, le halo de lumière brûle les yeux de Shedet qui découvre une jeune femme Sittiu un peu moins âgé que lui, agenouillée et simplement vêtue d’une robe de lin blanche. Ses cheveux noirs attachés par un chignon et ses yeux bleus encore entouré de fard prouve qu’elle est une Sittiu et tout comme le vieux au chat, celle-la semble aussi se cacher des Égyptiens.
— Qui es-tu? demande sèchement Shedet. — Je… je suis une fugitive du nome Des Deux Divinités, à l’Ouest de Bast… je m’appelle… La jeune demoiselle cherche ses mots, ses doigts tremblent et son souffle est irrégulier. « Soit elle dit vrai, soit elle feint d’avoir perdu la mémoire et dans ce cas c’est une ennemie. Le tueur est encore là ou c’est peut-être elle? Pour l’instant je jurerai qu’elle ment, on dirait qu’elle récupère d’un sprint».
— Donne moi ta torche! ordonne Shedet en s’approchant d’elle en un éclair. D’un bond la demoiselle se lève et cache sa main gauche dans son dos tout en éblouissant le déchu avec les flammes. « Ses genoux sont sales, couverts de terre et de sang qui ne semble pas être le sien, elle n’arbore aucune blessure aussi grave. Sa respiration est bien celle de quelqu’un ayant courut plus longtemps qu’a l’accoutumé et de plus elle ne semble pas vouloir s’échapper de la grotte. Gagne-t-elle du temps? ».
— Je te préviens je ne me gênerai pas pour te frapper alors donne-moi cette torche! Du coin de l’oeil Shedet aperçoit un vêtement mis en boule mais plus surprenant le reflet d’un objet en laiton attire subitement son regard. Soudain une lame tente de lui perforer la gorge, la jeune demoiselle rate de peu son attaque donnant ainsi à Shedet une raison suffisante pour l’agresser. De sa main droite il étrangle demoiselle et de l’autre il la désarme faisant tomber la torche. Les flammes s’amenuisent, l’assaillante est exténuée et peine à se défendre.
— Maintenant tu vas me dire qui tu es! As-tu un complice? — Non pitié me tues pas! Tu me fais mal! La douce peau pâle de cette femme, au contact de sa main rugueuse, est si agréable pour lui. Aussi lisse que les pierres polies qu’il taille au chantier. Toutefois au fond de lui, Shedet sent monter une sorte de plaisir à l’entendre gémir, un sentiment qu’il n’avait jamais ressenti. Entre les petits cris de la demoiselle Shedet distingue le son d’un éboulement à l’arrière, exactement à l’entrée de la grotte.
— Quelqu’un d’autre est ici? interroge-t-il la voix paniqué. — Non il n’y a que moi, s’étouffe-t-elle. — Alors c’est bien toi qui tues les gardes… — L’égyptien! Relâche-la immédiatement! ordonne une voix familière et désagréable.
Shedet se retourne en prenant en otage la demoiselle, ou tueuse de garde d’après son hypothèse. Geburah apparait, il s’extirpe de la corniche, son apparence lui fait penser à un esprit prenant progressivement forme humaine à l’entrée de la grotte. Devant cette réunion improvisée, Shedet se tient prêt au cas où la situation dégénérerait. « Deux Sittiu qui souhaitent me priver de ma récompense. Je suis foutu. Amon viens-moi en aide ». Le moindre geste, le simple frottement d’un objet contre un autre crispe chacun des personnages piégés dans cette région maudite. Shedet se sent acculé par ce prédateur, dans le pire des cas il envisage de menacer d’exécuter la femme cependant Geburah semble sobre et dans cette situation il est toujours capable d’un exploit. « Tant pis, je refuse de mourir des mains de ce chien ». Il agrippe plus fortement la demoiselle au cou puis la menace avec la dague.
— Toi Geburah tu dégages immédiatement! Je le jure sur Anubis que cette femme aura la gorge tranchée si tu restes encore dans les parages. Le regard plein de haine, Geburah refuse de procéder au moindre mouvement. Il annonce d’un ton calme et déterminé:
— Si tu la relâches je te promets une mort rapide.
Shedet panique, il observe la sortie obstrué par le corps du Sittiu puis demande: — Toi aussi tu tues les gardes? — Bien sûr que non, même si j’aurai bien voulu le faire pourtant je n’ai jamais aimé les méthodes
de la secte des crocs d’Apep. Tuer des égyptiens nous est plus désavantageux et ces idiots ne veulent pas encore le comprendre.
— Alors il n’y a que toi qui assassine les gardes? demande Shedet à la demoiselle tout en serrant la lame contre sa gorge. — Pourquoi? panique-t-elle la voix tremblante, ils étaient tes amis? Ta famille? Un rire s’échappe de Shedet, l’écho se propage dans la grotte puis l’extérieur tandis que Geburah avance d’un pas. — Je hais les gardes autant que je vous déteste, répond Shedet, ces raclures m’ont aussi racketté. En fait je suis content de ton travail cependant il y a une récompense à la clé en échange de ta tête et je me fiche que tu sois une femme. Je dois à tout prix me sortir de cet enfer. La demoiselle s’agite moins jusqu’à cesser tout mouvement, Geburah se stoppe après quelques pas supplémentaire puis se retourne lorsque le bruit du mur s’effritant à l’entrée de la caverne devient plus pressant. Une main ensanglantée surgit puis un homme suffoquant et haletant, un intrus d’après la réaction du Sittiu. — T’es qui toi? demande Geburah un peu paniqué en voyant l’allure pitoyable de l’homme. Difficile pour Shedet d’apercevoir l’identité de l’intrus, le corps de Geburah lui gâche la vue toutefois il discerne une posture familière. L’intrus est courbé, le bras se tenant fermement le flanc gauche tandis que l’autre brandit un poignard suintant régulièrement un liquide. « C’est le déchu de tout à l’heure! Il pourrait m’aider dans cette impasse, si il détourne l’attention de ce chien de Geburah je l’assassinerai sans problème ». — Toi là! interpelle Shedet à l’intrus. Nous sommes du même sang, aide-moi à sortir d’ici et nous nous partagerons la récompense. L’individu, sans doute en voyant aussi l’impasse et son désavantage, pointe sa lame en direction de l’ancien contremaître. Etant derrière Geburah la partie n’est plus à son avantage. — Je veux aussi la récompense, déclare l’intrus d’une voix haletante. — Oui tu l’auras, répond Shedet, mais ce chien de Geburah est notre seul obstacle. « Crétin. Après l’entaille que tu m’as faite à la joue je te pousserai dans le vide une fois le danger écarté ». La demoiselle, calme jusqu’à présent, crie: — Attendez! S’il vous plaît nous pouvons trouver un arrangement. — Je t’en propose un femme, dit Shedet en appuyant la lame bien en évidence devant Geburah. Ne fais rien de stupide et tout se passera bien pour toi. — Non attends on peut s’arranger, répète-t-elle paniquée, je peux vous donner mieux que ce vous offrirai le nomarque pour ma tête. Shedet se met à rire face à ce qu’il considère être une bonne blague. Geburah tente de se rapprocher mais l’intrus exerce le même geste prêt à bondir sur sa proie malgré son apparence d’animal agonisant. — Très bien femme, je souhaite récupérer ma citoyenneté. Tu vas me faire croire que tu serais capable de réussir là où le nomarque échoue? — Justement je peux t’offrir mieux… La colère dévore les mains de Shedet resserrant sa prise et le couteau plus fortement que la mâchoire d’un crocodile. « Si je m’emporte je risque de la tuer et honnêtement je ne me sens pas prêt de le faire. Lui infliger autant de blessure commence à me rendre malade ». La pauvre demoiselle étouffe avant de pouvoir respirer de nouveau, Shedet est subitement pris de curiosité par ses paroles: — Allez, dis-moi ce que tu proposes? — Le poste de nomarque de Bast… — Sale cafard! menace Geburah, si tu la tues tu connaîtras le même sort. — Ferme-là chien ou je lui tranche la gorge. Désolé de te décevoir femme mais le poste est déjà occupé. — Justement nous ferons en sorte de t’y faire accéder, voire plus. — Comment ça nous? répond Geburah. — Pourquoi ne pas allier nos forces afin de faire s’élever cet égyptien dans les hautes sphères de ce royaume? — Afin de pouvoir me contrôler comme une poupée? Ton plan est stupide femme, ton piège est aussi gros qu’un éléphant. — Ecoutez, nous avons tous des rêves, la seule chose que je souhaite est de vivre dans un nome aux conditions décentes. Je refuse de voir mes enfants et petits enfants souffrir jusqu’à la mort à construire une pyramide aussi inutile qu’immense. La situation tendue devint beaucoup plus calme, la prononciation du mot rêve a réveillé quelque chose d’enfoui dans le coeur de chacun. La sincérité de cette femme est déconcertante elle sait manier les mots mais cela n’est pas sans malice d’après Shedet. Elle reprend: — Geburah j’ai beaucoup entendu parler de toi, mon mari est même sous tes ordres. — Etait. Aujourd’hui je ne fais plus rien, je suis totalement perdu et maintenant que je sais que tu es de mon peuple, je ne peux me résoudre à te livrer à Miysis. Mais tu vas devoir arrêter de massacrer les gardes. — Justement elle a tué des gardes, des Égyptiens je te rappelle. Elle doit souffrir pour cela, la loi de Pharaon lui exigera un bras et une jambe. — Oui de simples égyptiens, rétorque Geburah d’un sourire provocateur, moi cela me conviens. D’ailleurs je t’en remercie encore tueuse de garde pour ton courage. — Saleté de parasite, grogne Shedet, moi je n’aurai aucun scrupule à la livrer et encore moins à séparer sa tête de son corps. — Des mots, toujours des mots l’égyptien et depuis tout à l’heure tu n’as rien fait, ajoute Geburah en jetant un rapide coup d’oeil vers l’intrus. Geburah semble prendre l’avantage sur cette bataille il approche d’un pas tandis que l’intrus, toujours silencieux, s’adosse contre le mur tout en se tenant le ventre. Sa posture se casse davantage. — Ces gardes je les ai tués car ils menaçaient les membres de ma famille, c’étaient des hommes corrompus ne faisant pas leur travail correctement. Jeune égyptien tu sais que je dis la vérité. — Ils étaient Égyptiens et ont donc tous les droits sur vous. Ton crime est grave femme, la dernière fois que j’ai entendu parler d’un tueur d’Égyptien le Sittiu a agonisé deux longs jours dans le désert avant d’être empalé comme brochette pour les crocodiles. — Non pitié ne me dénonce pas! crie-t-elle en versant des larmes, ceux que j’ai tué avaient commis des crimes abjectes. L’un était un jeune connu pour ces nombreux viols sur de pauvres femmes de mon peuple. Malgré les alertes anonymes que j’avais effectuées mes appels étaient restés sans réponse, Miysis ne s’intéresse pas à son nome. Ayant peur que ce monstre s’attaque à ma fille je me suis chargé de l’éliminer en le poignardant. Je te jure sur mon honneur et le ToutPuissant que mes meurtres n’étaient pas gratuits, loin de là. Shedet relâche sa poigne en entendant ces mots, à la grande surprise de la demoiselle. Son histoire est véridique car des rumeurs planaient sur un garde du nom de Penidéb. Un être abjecte s’étant engagé, comme beaucoup d’autres, afin d’assouvir ses pulsions malsaines sur les Sittiu. Shedet finit par complètement lâcher la demoiselle qui se frotte le cou rougit et saignant par l’étranglement. Elle raconte une autre de ses péripéties afin d’améliorer la qualité de son plaidoyer. Celle du soldat retrouvé le cou brisé près d’une statue de Bastet vers le chantier Sud il y a deux semaines. D’après elle cet homme était connu comme racketteur, il dépouillait les pauvres Sittiu croisant sa route et demandait des compensations pour des lois inexistantes certaines fois. La malice alla plus loin lorsqu’il dénonça un commerce illégale fictif afin de pouvoir spolier la maison d’un ami de la tueuse. Pour éviter qu’un jour ce rat ne s’en prenne à sa famille elle le tua en le poussant du haut de son mirador là où il cachait son butin amassé malhonnêtement. — C’est bon j’ai compris! s’exaspère Shedet en sentant qu’elle allait poursuivre dans ses exemples. Tu es certaine de ce que tu avances? C’est à dire que si je vérifie tes propos sur ces soi-disant monstres je découvrirai les même vices? — Oui j’en ai même les preuves, je pensais que tuer quelques un feraient réagir les autres sur leurs comportements mais il en fut rien. — Tu me parles de tuer comme d’une chose banale et tu continues de penser que je vais te faire confiance? — Je suis consciente que mon attitude est étrange mais comprend moi. J’ai une famille. Tout cela je le fais pour mes trois enfants. Tuer me répugne, j’en fais encore des cauchemars avec des terreurs nocturnes mais si je dois continuer pour la sécurité de mes enfants alors qu’il en soit ainsi. Shedet la regarde avec mécontentement, « c’est pas vrai! Maintenant qu’elle a dit cela je n’ai plus envie de la livrer. Comment je fais maintenant pour la récompense? ». — Supposons que j’accepte de m’allier à toi, que ferons-nous? Comment saurais-je que tu ne vas pas me trahir? — Et bien je propose que nous faisions serment. Serment de réaliser l’objectif que nous allons nous fixer dans cette grotte. Notre propre secte. — L’idée me déplait fortement, dit Geburah, m’associer à ces égyptiens me donne la nausée rien que d’y penser. L’intrus ne réagit pas et s’effondre sans que personne ne lui viennent en aide, épuisé il ne fait qu’écouter cette réunion improvisée en tentant de ne pas s’endormir. — Si tu penses que je vais croire à tes mensonges femme, vous allez me poignarder dans le dos dès la fin de notre discussion… — Je te promets que ce ne sera pas le cas! Demande à Geburah, un serment chez les Sittiu est aussi sacré que la parole du Tout-Puissant. Le rompre expose le traître à une malédiction. « Il est vrai que si ils prêtent serment la garantie n’en sera que plus forte. Bon sang, je connais beaucoup trop bien leurs coutumes ». — Et pourquoi te croirais-je? Tu tues des Égyptiens toujours avec le même motif: ta famille. A t’entendre tu assassinerais notre grand Pharaon pour rallonger d’un jour l’espérance de vie de tes enfants. Le sérieux dans le regard de la tueuse donna envie à Shedet de lui asséner un coup de poing pour cet affront néanmoins sa mauvaise situation ne le dois pousser à commettre d’erreur. Geburah est encore à fleur de peau. La demoiselle se tourne vers ce dernier et déclare: — Je dois vous avouer un secret, surtout toi Geburah. Je ne fais pas partie de la secte des crocs d’Apep. — Mais alors tu usurpes leur nom! s’écrie le Sittiu en s’approchant encore d’un pas, comment ont-ils réagi en l’apprenant? Shedet recule suffisamment pour être loin de ces deux énergumènes cependant son dos se colle au mur froid et humide. « Bon sang! Par Thot je suis foutu, si jamais ils s’associent je finirai mes jours à pourrir sans sacrement dans ce trou. L’autre intrus ne me sera pas utile. Ô grand Amon protège moi de ces monstres ». — Ils ne le savent pas…enfin jusqu’à hier. Un message a été reçut et découvert ce matin dans le bazar, le lieu le plus fréquenté de Boubastis afin que tous puissent le voir. Heureusement personne, à part vous tous ici présent, savent réellement ce que je fais. — Ne t’en fais pas ton secret sera à jamais gardé entre ces murs, je t’en fais le serment. En revanche il va falloir tuer cet égyptien et achever l’autre. — Non! s’écrie-t-elle en le retenant. Tu n’as pas entendu le projet que j’ai proposé? Cet égyptien sera notre clé pour un nome plus sûr. Nous devons l’élever dans les hautes sphères. Geburah observe son ancienne proie sur la défensive, l’idée lui redonne un peu d’espoir pour son avenir. Il ajoute: — Très bien mais comment on va s’y prendre? — J’ai une idée, déclare Shedet, pour me prouver votre bonne foi je livre Geburah en prétextant qu’il était le tueur de garde. Tu as dit vouloir un but dans la vie alors pour ta foutue fierté de Sittiu, tu vas te rendre utile! — Jamais! Plutôt vivre dans le déshonneur que de mourrir pour un égyptien! — Du calme messieurs je vous prie, il y a un moyen plus sûr. Mais d’abord effectuons le serment afin de garantir notre bonne foi au déchu. Shedet ne se sent pas rassuré, la demoiselle utilise sa torche renversée sur le sol pour éclairer les flambeaux illuminant petit à petit cette grotte se transformant en repaire. Sur sa gauche, une grande table sculptée dans la pierre était dissimulée dans l’obscurité tout comme un panneau de bois où des inscriptions codées sont gravées en point et trait. Une carte grossière du nome fut dessinée mais la topographie doit être mise à jour. Sur sa droite se découvre une longue et large paillasse moelleuse pouvant accueillir une dizaine de personne sans problème. De l’eau putride dans un bidon, provenant sûrement du chantier, est également présent. — Vous ne rêvez pas, dit la demoiselle en allumant le dernier flambeau, c’était bien l’un des nombreux repaire de la secte mais avec la mort de Eber plus personne ne pouvait reprendre les affaires. — Donc c’est bien toi qui a volé les vêtements? demande Geburah. — Non, j’ai payé quelqu’un pour le faire mais ne t’en fais pas personne n’est au courant. Maintenant venez tous autour de la table. Toi aussi le déchu agonisant. La demoiselle souhaitait l’aider mais son comportement de bête sauvage la retint aussitôt, Geburah se place devant elle. — Le blessé, déclare Geburah, es-tu prêt à nous suivre dans ce serment? L’intrus se relève tant bien que mal, il s’agrippe au mur, trébuche puis après deux ou trois tentatives arrive à ses fins. La demoiselle souhaite sincèrement lui venir en aide mais son comportement et sa posture de pestiféré l’en dissuade. S’asseyant près de la table, l’intrus halète et expire de manière forcé, l’odeur qu’il dégage est semblable à un corps en décomposition. — Mon Dieu! s’écrie la demoiselle, quel mal te ronge autant? — Pas ton problème, dit lentement l’intrus. — Bon allez dépêchez-vous! s’impatiente Shedet en tapotant de ses doigts la table grise, je veux en finir au plus vite pour avoir ma récompense. Tous se mettent en place autour de la table ronde. Shedet observe avec attention le moindre mouvement de ces énergumènes. « Je me fiche que ce déchu soit dans le coup, au vu de son état il périra dans quelques jours et me laissera tranquille pour me concentrer sur ces deux Sittiu. Si je n’ai pas ma récompense je jure sur Thot qu’ils me le paieront ». La demoiselle prend la parole après avoir placé la torche au milieu de la table laissant apparaitre de l’eau en gouttelette et des morceaux de nourriture sec. Le visage des quatre personnages est éclairé par la faible lumière. — Je déclare solennellement la création du serment. Avant toute chose j’aimerai savoir ce qui vous a motivé dans la récompense. Un silence s’installe personne ne veut répondre, la demoiselle ajoute: — Très bien je commence, déjà pour commencer je me nomme Layâ, habitante de Boubastis au quartier Félis. Je suis lavandière le soir pour Miysis et boulangère la journée pour les hommes du chantier. Mon rêve est de vivre dans un nome où les Sittiu seraient en sécurité. Surtout pour mes enfants et leurs descendants. Shedet écoute à demi-mot ces paroles, ennuyé il s’apprêtait à vouloir faire accélérer les choses mais Geburah lui coupe l’herbe sous le pied. — Moi Geburah rêve de libérer mon peuple et libérer les Sittiu du joug des égyptiens. J’en suis convaincu car là est la volonté du Tout-Puissant. — Rêve stupide, marmonne Shedet en le dévisageant. Toutefois un sentiment étrange le parcouru, la phrase de Geburah ne lui paraissait pas sincère comme si il récitait une leçon apprise par coeur. — Je m’appelle Iouferséneb, pantelle-t-il, je veux devenir marchand, je veux pouvoir marchander à Ouaset. « Etrange pourquoi Ouaset? Cet homme est louche, son aura de cadavre me déplait fortement ». — Hé jeune égyptien, répète calmement Layâ à plusieurs reprises, tout va bien? — Finissons-en je voudrai ma récompense. — S’il te plait joue le jeu. — Très bien, je m’appelle Shedet et mon rêve est de devenir scribe en Haute-Égypte ou non dans le Cartouche. — C’est tout? dit-elle déçut. — Bah oui en quoi cela te concerne? — Soit un peu plus ambitieux, encourage-t-elle, pourquoi ne pas devenir…Vizir après être devenu nomarque. — Vizir? C’est une fonction uniquement dédié à la famille la plus noble du royaume. De toute manière même si je le pouvais je refuserai catégoriquement. — Pourquoi cela? demande Layâ; Shedet effectue de sa main un signe de ciseau d’un air assez gêné. Je ne comprends pas, que signifie ce symbole? — La castration, intervient Geburah, l’égyptien te fait comprendre qu’il perdra l’appareil entre ses jambes. Bande de dégénéré. — Du calme, rétorque Shedet, j’y tiens à mes parties. Mais je suis d’accord avec toi femme, devenir nomarque, si cela est possible, me permettrai d’atteindre mon objectif. — Au nom du Tout-Puissant je prête serment d’aider l’égyptien à atteindre son objectif, déclare Layâ les yeux fermés et les paumes des mains tendus vers le ciel. Geburah répète la phrase à contre-coeur tout comme Iouferséneb avec le peu d’énergie qui lui reste. — Au nom des dieux et de notre grand Pharaon maître des trois terres je jure de tout faire pour atteindre mon objectif. A ces mots Shedet se sentit emplit de courage.

I’m currently paying entirely too much where I am living and need to move out of my home. If anyone would be willing to roommate with a 26 non binary person with no pets, 420 friendly though I don’t partake often at all, my limit is 700 comfortably in order to save money and still pay my bills.

Hey everyone, so my housemate has been showing the laundry list of symptoms listed below and we recently went to the ER which after 10 hours of waiting; we were discharged after the doctor said he doesnt think the episodes are dangerous and are probably panic attacks. Looking for some more opinions since they've had panic attacks before, and they don't display anything like what they're experiencing now.
Symptoms: - Frequent episodes (detailed below) lasting anywhere from 1-2 hours - Feeling faint and as though they need to lie down - Numbness and tingling (pins and needles) in arms, legs, torso and up to base of neck and complete loss of movement in left hand side for duration - Laboured breathing with apparent pressure on the base of their throat (not hyperventilation) - Difficulty speaking and responding to questions - Difficulty focussing eyes; some double vision - When trying to move left limbs, right limbs twitch instead - Body feels cold during episodes After episodes and other info: - Nausea afterwards - Increasing frequency (3 in the last 36 hours, each an hour+ and the third being the worst). 4 total, first was 2 days ago. First and fourth significantly worse than second and third - After 1-2 hours they very slowly regain control over their body/limbs and numbness fades - Balance issues that come and go with the day but have slowly gotten worse since February - Not a tumor or cyst on the brain either, they've already had a CT which diagnosed a cyst but the DR said due to the scalloping on the skull it's likely been there for years and is unrelated to the episodes
I think that covers it. We've also looked into the symptoms as well and have concerns that it might be GBS (Guillain-Barré Syndrome) so if anyone has any further insights as to what might be the cause, please let us know so that we can either curb our worries or get appropriate testing done.
They do also have an MRI on their head tomorrow afternoon to hopefully help figure out what's happening. Any advice/information is greatly appreciated.
If it helps rule out anything region specific, we are located in Australia
Edit: My housemate is 23 and trans masc non-binary

it's also canon that all these three characters specifically are attracted to men, at least. It has been confirmed by members of the dev teams and by the OG creator and main writer, and it has been mentioned multiple times throughout the years.
You can look it up if you want, but here's a couple of things confirmed mentioned in interviews:
⭐️Edgeworth doesn't feel attraction for women at all, but does feel physically attracted to Phoenix (said by the original designer, Kumiko Suekane)
⭐️in one of the official manga anthologies, Edgeworth reminisces about his first crush, a boy he met in the rain and whose face he cannot remember. Later on, he realizes it was Phoenix with his hair down due to the rain all along. (Manga was oversaw and approved by Shu Takumi, OG creator and writer)
⭐️Phoenix has a preference for mature and cool women, and for cute men. He thinks Edgeworth is very cute (said by the OG creator and main writer, Shu Takumi)
⭐️From the second game onwards, it was confirmed that any and all gay tension and interactions shown in the games was written purposefully, with the intention of being read as gay. (Confirmed by Shu Takumi, who also mentioned that all the dev team knew and contributed, even to the point of reading a mountain of gay manga/yaoi together to learn how to write homoerotic tension properly, but didn't tell the higher ups until the game was already out be they knew if the higher ups caught up with what they were doing, they wouldn't let the games be released)
⭐️Klavier does in fact feel attracted to Apollo, but as he himself mentioned, as it is the first time he felt this way with a man, he doesn't know how to deal with it very well (as said by Shu Takumi)
⭐️In multiple side stories, Klavier tries to invite Apollo to dates, with Apollo always rejecting him due to believing Klavier is just joking around and leaving Klavier depressed as a running gag. (Stories all written by Shu Takumi & other production members from the games. It is also mentioned in one of said stories that if Apollo realized Klavier was being serious all along, he would actually accept to go in a date with him)
⭐️Asougi is, in fact, in love with Ryuunosuke, even if the latter's attraction for him hasn't been confirmed. It's the first time he has felt this way for someone, so he gets a lil' too excited and tries harder than he ought to, with most of his advances ending being unnoticed by Ryuunosuke who thinks its just Asougi being his usual intense self. Truthfully, Asougi is usually a guy of very few words, a taciturn and quiet person who almost always looked annoyed by everything around him and replied coldly to basically anyone who tried to strike conversation with him who weren't the Mikotoba family. Everyone who had known Asougi before his meeting with Ryuunosuke were shocked by the change in attitude, as most even went as far as thinking Asougi was unable to smile, so to see him laugh so freely and frequently now due to one person was unbelievable in their eyes. The Mikotobas noticed the change, too, and when they asked about it to Asougi, he literally replied with " met the love of my life". ( All as said by both Shu Takumi, main writer and OG creator, and Kazuya Nuri, TGAA's character designer. The latter in particular is a die-hard Asougi x Naruhodou shipper, and an even bigger Susato × Haori/Rei shipper)
⭐️Asougi thinks Ryuunosuke is adorable, handsome, manly and beautiful, believing there doesn't exist a more breathtaking sight that him. (As confirmed by Shu Takumi)
⭐️Asougi has fallen in love with Ryuunosuke at least twice, with an additional one implied. The first, when they met as kids by chance, were he asked Ryuunosuke to marry him, but Ryuunosuke thought Asougi wanted to kill him due to the word "marrying" and "bloodstain" being pronounced the same in japanese, "kekkon", and the second was when they met again years later, having forgotten their real first meeting as children. The implied one is when he saw Ryuunosuke for the first time as the Masked Apprentice, as it's mentioned that while he did stop to look at "the smaller man in the office" cuz he felt he recognized him from somewhere, the actual reason why he kept staring at Ryuunosuke for such a long period of time afterwards was because he found "the smaller man with big eyes" to be "very handsome" to the point the Masked Apprentice felt that "he wouldn't feel tired of looking at him". (As said by Kazuya Nuri, TGAA's character designer).
⭐️As he has no experience whatsoever with those types of feelings, Asougi can't help but constantly "pour warm love/tea" on Ryuunosuke, a japanese expression used for people who are very, very affectionate and pampering towards the person they've fallen in love with (as said by Shi Takumi on magazine)
⭐️On one of the side stories, Ryuunosuke is eating a lunch made by Asougi, and says that he "would be happy to eat Asougi's food every day". Ryuunosuke said it without thinking to much about it, and didn't realize that Asougi got super happy hearing that, being on an extremely good, chipper mood for a couple of days afterwards. This is because "I want to eat your food every day" is a common way to propose on Japan, so Asougi felt as if Ryunosuke was saying that he would be happy to marry him. Multiple side stories between the two make more comparisons/jabs and winks to married life, such as the one where they "shared a red umbrella while walking through the snow, the path looking like a wedding road". In traditional Japanese weddings, the bride and groom walk together a road with rice and white petals thrown in tbe floor while sharing a red umbrella. (All side stories written by Shu Takumi, published in Capcom's official website) Like, idk what to tell you my man, but all these lawyers seem pretty gay to me. Specially the samurai lawyer, calling the homie you just met last week "the love of your life" seems pretty unambiguous to me
I mean, if you wanna headcanon 'em as pure platonic cuz you feel uncomfortable or something, go ahead, but that wouldn't be canon, either, so you cannot go around and say what you think is canon is the "actual canon" when proof of the contrary is very easy to find in this particular case, my man. It's true shippers tend to blow stuff out of proportions, but in this case, it's you who 1. Is in the wrong, and 2. Is being an hypocrite. If you really cared so much about what's canon and what's not, you would at least know the stuff about Edgeworth, which is the most easily accessible for people in the west. Seriously, you sound like the fans of Transformers who insist Optimus Prime wouldn't support the LGBTQ+, when all the Transformers cast has been confirmed to be part of the LGBTQ+ and Optimus' best friend is a trans lesbian. (Yes, All of 'em are part of the LGBTQ+ cuz their entire species has been confirmed to be non-binary, asexual, panromantic, genderfluid, trans robots, as they don't have the same views on gender identity and orientation as humans, feel no physical attraction and choose and change their genders by themselves, changing it again whenever they feel like another gender)
gay lawyers real fr

Hey /ChatGPTCoding, One of the major frustrations I've had (and others too from posts I've seen) with building projects w/ LLMs is dealing with the complexity of chunking/embedding/vector dbs, especially if you're in the non-python world.
At the end of the day I want to add content to storage and do a search to grab the context I need to send to the language model. So I built a dead-simple "LLM memory" service:

1. Run the service via a single cross-platform binary (or run in Docker)
2. Add content via `curl` or whatever RESTful client of choice
3. Query and get the context you need to pass to your LLM of choice.
4. ...
5. Enjoy! No need to deal with embeddings, figuring out how to split docs, running a vector db or any of that mess.

Here's a little demo of it in action adding the state of the union address and then doing a search to fine relevant content:
Run. Add content. Query. That's it!
I plan on open sourcing this. I wanted to get some feedback on the project and see if there are any "demo" projects that you'd like to see.

Hey /LocalLLaMA,
One of the major frustrations I've had (and others too from posts I've seen) with building projects w/ LLMs is dealing with the complexity of chunking/embedding/vector dbs, especially if you're in the non-python world.
At the end of the day I want to add content to storage and do a search to grab the context I need to send to the language model. So I built a dead-simple "LLM memory" service:

1. Run the service via a single cross-platform binary (or run in Docker)
2. Add content via `curl` or whatever RESTful client of choice
3. Query and get the context you need to pass to your LLM of choice.
4. ...
5. Enjoy! No need to deal with embeddings, figuring out how to split docs, running a vector db or any of that mess.

Here's a little demo of it in action adding the state of the union address and then doing a search to fine relevant content
Start. Add content. Query. That's it!
Looking to open source this soon!
I wanted to get some feedback on the project and see if there are any "demo" projects that you'd like to see.

1. Digital Communication 14.1. Introduction to Digital Communication Digital communication is made from two words - digital and communication. Digital refers to the discrete time-varying signal. Communication refers to the exchange of information between two or more sources. Digital communication as a whole refers to the exchange of digital information between the sender and receiver using different devices and methods. The data transmission using analog methods for long-distance communication suffers from distortion, delays, interferences, and other losses. To overcome these problems, the digitization and sampling of signals using different techniques help in making the transmission process more efficient, clear, and accurate. Digital communication is a popular technology used today in electronics. It allows us to access video conferencing, digital meetings, online education, etc. The data can travel up to long distances within a second with the help of the internet and other modes of digital communication. It not only saves money but also saves time and effort. It has also raised the standard of an individual's social, political, and economic life. 14.2. Networks and Busses The wires between the tank and the monitoring location is called a bus or a network. The distinction between these two terms is more semantic than technical, and the two may be used interchangeably for all practical purposes. The term “bus” is usually used in reference to a set of wires connecting digital components within the enclosure of a computer device, and “network” is for something that is physically more widespread. There are many types of buses and networks. Each one has its own applications, advantages, and disadvantages. 12.2.1. Short-distance busses 12.2.1.1. PC/AT Bus used in early IBM-compatible computers to connect peripheral devices such as disk drive and sound cards to the motherboard of the computer.

12.2.1.2. PCI Another bus used in personal computers, but not limited to IBM-compatibles. Much faster than PC/AT. Typical data transfer rate of 100 Mbytes/second (32 bit) and 200 Mbytes/second (64 bit). 12.2.1.3. PCMCIA A bus designed to connect peripherals to laptop and notebook sized personal computers. Has a very small physical “footprint,” but is considerably slower than other popular PC buses. 12.2.1.4. VME A high-performance bus (co-designed by Motorola, and based on Motorola’s earlier Versa-Bus standard) for constructing versatile industrial and military computers, where multiple memory, peripheral, and even microprocessor cards could be plugged in to a passive “rack” or “card cage” to facilitate custom system designs. Typical data transfer rate of 50 Mbytes/second (64 bits wide). 12.2.1.5. VXI An expansion of the VME bus, VXI (VME eXtension for Instrumentation) includes the standard VME bus along with connectors for analog signals between cards in the rack. 12.2.1.6. S-100 Sometimes called the Altair bus, this bus standard was the product of a conference in 1976, intended to serve as an interface to the Intel 8080 microprocessor chip. Similar in philosophy to the VME, where multiple function cards could be plugged in to a passive “rack,” facilitating the construction of custom systems.
12.2.1.7. MC6800 The Motorola equivalent of the Intel-centric S-100 bus, designed to interface peripheral devices to the popular Motorola 6800 microprocessor chip. 12.2.1.8. STD Stands for Simple-To-Design and is yet another passive “rack” similar to the PC/AT bus, and lends itself well toward designs based on IBM-compatible hardware. Designed by Pro-Log, it is 8 bits wide (parallel), accommodating relatively small (4.5 inch by 6.5 inch) circuit cards. 12.2.1.9. Multibus I and II Another bus intended for the flexible design of custom computer systems, designed by Intel. 16 bits wide (parallel). 12.2.1.10. CompactPCI An industrial adaptation of the personal computer PCI standard, designed as a higher-performance alternative to the older VME bus. At a bus clock speed of 66 MHz, data transfer rates are 200 Mbytes/ second (32 bit) or 400 Mbytes/sec (64 bit). 12.2.1.11. Microchannel Yet another bus, this one designed by IBM for their ill-fated PS/2 series of computers, intended for the interfacing of PC motherboards to peripheral devices. 12.2.1.12. IDE A bus used primarily for connecting personal computer hard disk drives with the appropriate peripheral cards. Widely used in today’s personal computers for hard drive and CD-ROM drive interfacing.
12.2.1.13. SCSI An alternative (technically superior to IDE) bus used for personal computer disk drives. SCSI stands for Small Computer System Interface. Used in some IBM- compatible PC’s, as well as Macintosh (Apple), and many mini and mainframe business computers. Used to interface hard drives, CD-ROM drives, floppy disk drives, printers, scanners, modems, and a host of other peripheral devices. Speeds up to 1.5 Mbytes per second for the original standard. 12.2.1.14. GPIB (IEEE 488) General Purpose Interface Bus, also known as HPIB or IEEE 488, which was intended for the interfacing of electronic test equipment such as oscilloscopes and multimeters to personal computers. 8 bit wide address/data “path” with 8 additional lines for communications control. 12.2.1.15. Centronics parallel Widely used on personal computers for interfacing printer and plotter devices. Sometimes used to interface with other peripheral devices, such as external ZIP (100 Mbyte floppy) disk drives and tape drives. 12.2.1.16. USB Universal Serial Bus, which is intended to interconnect many external peripheral devices (such as keyboards, modems, mice, etc.) to personal computers. Long used on Macintosh PC’s, it is now being installed as new equipment on IBM-compatible machines. 12.2.1.17. FireWire (IEEE 1394) A high-speed serial network capable of operating at 100, 200, or 400 Mbps with versatile features such as “hot swapping” (adding or removing devices with the power on) and flexible topology. Designed for high-performance personal computer interfacing.
12.2.1.18. Bluetooth A radio-based communications network designed for office linking of computer devices. Provisions for data security designed into this network standard. 12.2.2. Extended-distance networks 12.2.2.1. 20 mA current loop Not to be confused with the common instrumentation 4-20 mA analog standard, this is a digital communications network based on interrupting a 20 mA (or sometimes 60 mA) current loop to represent binary data. Although the low impedance gives good noise immunity, it is susceptible to wiring faults (such as breaks) which would fail the entire network. 12.2.2.2. RS-232C The most common serial network used in computer systems, often used to link peripheral devices such as printers and mice to a personal computer. Limited in speed and distance (typically 45 feet and 20 kbps, although higher speeds can be run with shorter distances). I’ve been able to run RS-232 reliably at speeds more than 100 kbps, but this was using a cable only 6 feet long! RS- 232C is often referred to simply as RS-232 (no “C”). 12.2.2.3. RS-422A/RS-485 Two serial networks designed to overcome some of the distance and versatility limitations of RS-232C. Used widely in industry to link serial devices together in electrically “noisy” plant environments. Much greater distance and speed limitations than RS-232C, typically over half a mile and at speeds approaching 10 Mbps. 12.2.2.4. Ethernet (IEEE 802.3) A high-speed network which links computers and some types of peripheral devices together. “Normal” Ethernet runs at a speed of 10 million bits/second, and “Fast” Ethernet runs at 100 million bits/second. The slower (10 Mbps) Ethernet has been implemented in a variety of means on copper
wire (thick coax = “10BASE5”, thin coax = “10BASE2”, twisted-pair = “10BASE- T”), radio, and on optical fiber (“10BASE-F”). The Fast Ethernet has also been implemented on a few different means (twisted-pair, 2 pair = 100BASE-TX; twisted-pair, 4 pair = 100BASE-T4; optical fiber = 100BASE-FX). 12.2.2.5. Token ring Another high-speed network linking computer devices together, using a philosophy of communication that is much different from Ethernet, allowing for more precise response times from individual network devices, and greater immunity to network wiring damage. 12.2.2.6. FDDI A very high-speed network exclusively implemented on fiber-optic cabling. 12.2.2.7. Modbus/Modbus Plus Originally implemented by the Modicon corporation, a large maker of Programmable Logic Controllers (PLCs) for linking remote I/O (Input/Output) racks with a PLC processor. Still quite popular. 12.2.2.8. Profibus Originally implemented by the Siemens corporation, another large maker of PLC equipment. 12.2.2.9. Foundation Fieldbus A high-performance bus expressly designed to allow multiple process instruments (transmitters, controllers, valve positioners) to communicate with host computers and with each other. May ultimately displace the 4-20 mA analog signal as the standard means of interconnecting process control instrumentation in the future.
14.3. Data Flow Buses and networks are designed to allow communication to occur between individual devices that are interconnected. The flow of information, or data, between nodes, can take a variety of forms: With simplex communication, all data flow is unidirectional: from the designated transmitter to the designated receiver. BogusBus is an example of simplex communication, where the transmitter sent information to the remote monitoring location, but no information is ever sent back to the water tank. If all we want to do is send information one-way, then simplex is just fine. Most applications, however, demand more: With duplex communication, the flow of information is bi- directional for each device. Duplex can be further divided into two sub- categories:
The Half-Duplex works like a type of communication, that may be likened to two tin cans on the ends of a single taut string: Either can may be used to transmit or receive, but not at the same time. Full-duplex communication is more like a true telephone, where two people can talk at the same time and hear one another simultaneously, the mouthpiece of one phone transmitting the earpiece of the other, and vice versa. Full-duplex is often facilitated through the use of two separate channels or networks, with an individual set of wires for each direction of communication. It is sometimes accomplished by means of multiple-frequency carrier waves, especially in radio links, where one frequency is reserved for each direction of communication.
14.5. Optical Data Communication A modern alternative to sending (binary) digital information via electric voltage signals is to use optical (light) signals. Electrical signals from digital circuits (high/low voltages) may be converted into discrete optical signals (light or no light) with LEDs or solid-state lasers. Likewise, light signals can be translated back into electrical form by photodiodes or phototransistors for introduction into the inputs of gate circuits. Transmitting digital information in optical form may be done in open air, simply by aiming a laser at a photodetector at a remote distance, but interference with the beam in the form of temperature inversion layers, dust, rain, fog, and other obstructions can present significant engineering problems:
One way to avoid the problems of open-air optical data transmission is to send the light pulses down an ultra-pure glass fibre. Glass fibres will “conduct” a beam of light much as a copper wire will conduct electrons, with the advantage of completely avoiding all the associated problems of inductance, capacitance, and external interference plaguing electrical signals. Optical fibres keep the light beam contained within the fibre core by a phenomenon known as total internal reflectance. An optical fibre is composed of two layers of ultra- pure glass, each layer made of glass with a slightly different refractive index, or capacity to “bend” light. With one type of glass concentrically layered around a central glass core, light introduced into the central core cannot escape outside the fibre, but is confined to travel within the core: Optical fibres exceed the data-handling performance of copper wire in almost every regard. They are totally immune to electromagnetic interference and have very high bandwidths. However, they are not without certain weaknesses.
14.6. Network Topology 14.6.1. Point-to-Point Connecting two digital devices with a network, would have a kind of network known as “point-to-point:” The network wiring is symbolized as a single line between the two devices. It may be a twisted pair of wires, a coaxial cable, an optical fibre, or even a seven-conductor BogusBus. 14.6.2. Bus Topology A type of network which uses a common transmission medium where all nodes of network are connected to it.
14.6.3. Star Topology A type of network that uses a hub, switch, or computer to act as a central network and which all the nodes connect to it. The selected hub, switch or computer acts as a server. 14.6.4. Ring Topology This topology provides the best reliability with the least amount of wiring. Since each node has two connection points to the ring, a single break in any part of the ring doesn’t affect the integrity of the network.
14.7. Network Protocols The standardized method by which nodes are allowed to transmit to the bus or network wiring is called a protocol. There are many different protocols for arbitrating the use of a common network between multiple nodes, and I’ll cover just a few here. However, it is good to be aware of these few, and to understand why some work better for some purposes than others. Usually, a specific protocol is associated with a standardized type of network. This is merely another “layer” to the set of standards which are specified under the titles of various networks. The International Standards Organization (ISO) has specified a general architecture of network specifications in their DIS7498 model (applicable to most any digital network). Consisting of seven “layers,” this outline, named the Open Systems Interconnection Layer (OSI Layer) attempts to categorize all levels of abstraction necessary to communicate digital data. Level 1: Physical Specifies electrical and mechanical details of communication: wire type, connector design, signal types and levels. Level 2: Data link Defines formats of messages, how data is to be addressed, and error detection/correction techniques. Level 3: Network Establishes procedures for encapsulation of data into “packets” for transmission and reception. Level 4: Transport Among other things, the transport layer defines how complete data files are to be handled over a network. Level 5: Session Organizes data transfer in terms of beginning and end of a specific transmission. Analogous to job control on a multitasking computer operating system.
Level 6: Presentation Includes definitions for character sets, terminal control, and graphics commands so that abstract data can be readily encoded and decoded between communicating devices. Level 7: Application The end-user standards for generating and/or interpreting communicated data in its final form. In other words, the actual computer programs using the communicated data. 14.8. Practical considerations - Digital Communication A principal consideration for industrial control networks, where the monitoring and control of real-life processes must often occur quickly and at set times, is the guaranteed maximum communication time from one node to another. The ability for a network to guarantee data “throughput” is called determinism. A deterministic network has a guaranteed maximum time delay for data transfer from node to node, whereas a non-deterministic network does not. The preeminent example of a non-deterministic network is Ethernet, where the nodes rely on random time-delay circuits to reset and re-attempt transmission after a collision.

1. Digital-Analog Conversion 13.1. Introduction to Digital-Analog Conversion A digital signal is a signal that represents data as a sequence of discrete values; at any given time, it can only take on one of a finite number of values. An analog signal is any continuous signal for which the time varying feature of the signal is a representation of some other time varying quantity i.e., analogous to another time varying signal.

The following techniques can be used for Digital to Analog Conversion: 1. Amplitude Shift keying – Amplitude Shift Keying is a technique in which carrier signal is analog and data to be modulated is digital. The amplitude of analog carrier signal is modified to reflect binary data. The binary signal when modulated gives a zero value when the binary data represents 0 while gives the carrier output when data is 1. The frequency and phase of the carrier signal remain constant. Advantages of amplitude shift Keying – It can be used to transmit digital data over optical fiber; the receiver and transmitter have a simple design which also makes it comparatively inexpensive; it uses lesser bandwidth as compared to FSK thus it offers high bandwidth efficiency. Disadvantages of amplitude shift Keying – It is susceptible to noise interference and entire transmissions could be lost due to this; it has lower power efficiency. 2. Frequency Shift keying – In this modulation the frequency of analog carrier signal is modified to reflect binary data. The output of a frequency shift keying modulated wave is high in frequency for a binary high input and is low in frequency for a binary low input. The amplitude and phase of the carrier signal remain constant.
Advantages of frequency shift Keying – Frequency shift keying modulated signal can help avoid the noise problems beset by ASK; it has lower chances of an error; it provides high signal to noise ratio; the transmitter and receiver implementations are simple for low data rate application. Disadvantages of frequency shift Keying – It uses larger bandwidth as compared to ASK thus it offers less bandwidth efficiency; it has lower power efficiency. 3. Phase Shift keying – In this modulation the phase of the analog carrier signal is modified to reflect binary data. The amplitude and frequency of the carrier signal remains constant. It is further categorized as follows: 1. Binary Phase Shift Keying (BPSK): BPSK also known as phase reversal keying or 2PSK is the simplest form of phase shift keying. The Phase of the carrier wave is changed according to the two binary inputs. In Binary Phase shift keying, difference of 180 phase shift is used between binary 1 and binary 0. This is regarded as the most robust digital modulation technique and is used for long distance wireless communication. 2. Quadrature phase shift keying: This technique is used to increase the bit rate i.e. we can code two bits onto one single element. It uses four phases to encode two bits per symbol. QPSK uses phase shifts of multiples of 90 degrees. It has double data rate carrying capacity compared to BPSK as two bits are mapped on each constellation points. Advantages of phase shift Keying – It is a more power efficient modulation technique as compared to ASK and FSK; it has lower chances of an error; it allows data to be carried along a communication signal much more efficiently as compared to FSK. Disadvantages of phase shift Keying – It offers low bandwidth efficiency; the detection and recovery algorithms of binary data is very complex; it is a non- coherent reference signal.
13.2. The 2nR DAC: Binary-Weighted-Input Digital-to-Analog Converter The 2nR DAC circuit, otherwise known as the binary-weighted-input DAC, is a variation on the inverting summing op-amp circuit. (Note that "summing" circuits are sometimes also referred to as "summer" circuits.) The classic inverting summing circuit is an operational amplifier using negative feedback for controlled gain, with several voltage inputs and one voltage output. The output voltage is the inverted (opposite polarity) sum of all input voltages: For a simple inverting summing circuit, all resistors must be of equal value. If any of the input resistors were different, the input voltages would have different degrees of effect on the output, and the output voltage would not be a true sum. 13.3. The 2R DAC (Digital-to-Analog Converter) The 2R DAC circuit is an alternative to the binary-weighted-input (2nR) DAC which uses fewer unique resistor values. A disadvantage of the former DAC design was its requirement of several different precise input resistor values: one unique value per binary input bit. Manufacture may be simplified if there are fewer different resistor values to purchase, stock, and sort prior to assembly. Of course, we could take the binary-weighted-input DAC circuit and modify it to use a single input resistance value, by connecting multiple resistors together in series:
Unfortunately, this approach merely substitutes one type of complexity for another: volume of components over diversity of component values. There is, however, a more efficient design methodology. By constructing a different kind of resistor network on the input of our summing circuit, we can achieve the same kind of binary weighting with only two kinds of resistor values, and with only a modest increase in resistor count. This “ladder” network looks like this: Mathematically analyzing this ladder network is a bit more complex than for the previous circuit, where each input resistor provided an easily-calculated gain for that bit.
13.4. Flash ADC Also called the parallel A/D converter, this circuit is the simplest to understand. It is formed of a series of comparators, each one comparing the input signal to a unique reference voltage. The comparator outputs connect to the inputs of a priority encoder circuit, which then produces a binary output. The following illustration shows a 3-bit flash ADC circuit: Vref is a stable reference voltage provided by a precision voltage regulator as part of the converter circuit, not shown in the schematic. As the analog input voltage exceeds the reference voltage at each comparator, the comparator outputs will sequentially saturate to a high state. The priority encoder generates a binary number based on the highest-order active input, ignoring all other active inputs. When operated, the flash ADC produces an output that looks something like this:
13.5. Digital Ramp ADC Also known as the stairstep-ramp, or simply counter A/D converter, this is also fairly easy to understand but unfortunately suffers from several limitations. The basic idea is to connect the output of a free-running binary counter to the input of a DAC, then compare the analog output of the DAC with the analog input signal to be digitized and use the comparator’s output to tell the counter when to stop counting and reset. The following schematic shows the basic idea: The effect of this circuit is to produce a DAC output that ramps up to whatever level the analog input signal is at, output the binary number corresponding to that level, and start over again. Plotted over time, it looks like this:
Note how the time between updates (new digital output values) changes depending on how high the input voltage is. For low signal levels, the updates are rather close-spaced. For higher signal levels, they are spaced further apart in time: For many ADC applications, this variation in update frequency (sample time) would not be acceptable. This, and the fact that the circuit’s need to count all the way from 0 at the beginning of each count cycle makes for relatively slow sampling of the analog signal, places the digital-ramp ADC at a disadvantage to other counter strategies. 13.6. Successive Approximation ADC One method of addressing the digital ramp ADC’s shortcomings is the so-called successive-approximation ADC. The only change in this design is a very special counter circuit known as a successive-approximation register. Instead of counting up in binary sequence, this register counts by trying all values of bits starting with the most-significant bit and finishing at the least-significant bit. Throughout the count process, the register monitors the comparator’s output to see if the binary count is less than or greater than the analog signal input, adjusting the bit values accordingly. The way the register counts is identical to the “trial-and-fit” method of decimal-to-binary conversion, whereby different values of bits are tried from MSB to LSB to get a binary number that equals the original decimal number. The advantage to this counting strategy is much faster results: the DAC output converges on the analog signal input in much larger steps than with the 0-to-full count sequence of a regular counter. Without showing the inner workings of the successive-approximation register (SAR), the circuit looks like this:
It should be noted that the SAR is generally capable of outputting the binary number in serial (one bit at a time) format, thus eliminating the need for a shift register. Plotted over time, the operation of a successive-approximation ADC looks like this:
13.7. Tracking ADC A third variation on the counter-DAC-based converter theme is, in my estimation, the most elegant. Instead of a regular “up” counter driving the DAC, this circuit uses an up/down counter. The counter is continuously clocked, and the up/down control line is driven by the output of the comparator. So, when the analog input signal exceeds the DAC output, the counter goes into the “count up” mode. When the DAC output exceeds the analog input, the counter switches into the “count down” mode. Either way, the DAC output always counts in the proper direction to track the input signal. Notice how no shift register is needed to buffer the binary count at the end of a cycle. Since the counter’s output continuously tracks the input (rather than counting to meet the input and then resetting back to zero), the binary output is legitimately updated with every clock pulse. An advantage of this converter circuit is speed, since the counter never has to reset. Note the behavior of this circuit:
Note the much faster update time than any of the other “counting” ADC circuits. Also note how at the very beginning of the plot where the counter had to “catch up” with the analog signal, the rate of change for the output was identical to that of the first counting ADC. Also, with no shift register in this circuit, the binary output would actually ramp up rather than jump from zero to an accurate count as it did with the counter and successive approximation ADC circuits. 13.8. Slope (integrating) ADC It is possible to avoid using a DAC if we substitute an analog ramping circuit and a digital counter with precise timing. The is the basic idea behind the so- called single-slope, or integrating ADC. Instead of using a DAC with a ramped output, we use an op-amp circuit called an integrator to generate a sawtooth waveform which is then compared against the analog input by a comparator. The time it takes for the sawtooth waveform to exceed the input signal voltage level is measured by means of a digital counter clocked with a precise- frequency square wave (usually from a crystal oscillator). The basic schematic diagram is shown here:
This ADC circuit behaves very much like the digital ramp ADC, except that the comparator reference voltage is a smooth sawtooth waveform rather than a “stairstep:” The single-slope ADC suffers all the disadvantages of the digital ramp ADC, with the added drawback of calibration drift. The accurate correspondence of this ADC’s output with its input is dependent on the voltage slope of the integrator being matched to the counting rate of the counter (the clock frequency). With the digital ramp ADC, the clock frequency had no effect on conversion accuracy, only on update time. In this circuit, since the rate of integration and the rate of count are independent of each other, variation between the two is inevitable as it ages, and will result in a loss of accuracy.
The only good thing to say about this circuit is that it avoids the use of a DAC, which reduces circuit complexity. An answer to this calibration drift dilemma is found in a design variation called the dual-slope converter. In the dual-slope converter, an integrator circuit is driven positive and negative in alternating cycles to ramp down and then up, rather than being reset to 0 volts at the end of every cycle. This technique of analog-to-digital conversion escapes the calibration drift problem of the single- slope ADC because both the integrator’s integration coefficient (or “gain”) and the counter’s rate of speed are in effect during the entire “winding” and “unwinding” cycle portions. If the counter’s clock speed were to suddenly increase, this would shorten the fixed time period where the integrator “winds up” (resulting in a lesser voltage accumulated by the integrator), but it would also mean that it would count faster during the period of time when the integrator was allowed to “unwind” at a fixed rate. Another important advantage of this method is that the input signal becomes averaged as it drives the integrator during the fixed-time portion of the cycle. Any changes in the analog signal during that period of time have a cumulative effect on the digital output at the end of that cycle. 13.9. Delta-Sigma ADC One of the more advanced ADC technologies is the so-called delta-sigma, or ΔΣ (using the proper Greek letter notation). In mathematics and physics, the capital Greek letter delta (Δ) represents difference or change, while the capital letter sigma (Σ) represents summation: the adding of multiple terms together. Sometimes this converter is referred to by the same Greek letters in reverse order: sigma-delta, or ΣΔ. In a ΔΣ converter, the analog input voltage signal is connected to the input of an integrator, producing a voltage rate-of-change, or slope, at the output corresponding to input magnitude. This ramping voltage is then compared against ground potential (0 volts) by a comparator. The comparator acts as a sort of 1-bit ADC, producing 1 bit of output (“high” or “low”) depending on whether the integrator output is positive or negative. The comparator’s output is then latched through a D-type flip-flop clocked at a high frequency and fed back to another input channel on the integrator, to drive the integrator in the direction of a 0 volt output. The basic circuit looks like
13.10. Practical Considerations of ADC Circuits Perhaps the most important consideration of an ADC is its resolution. Resolution is the number of binary bits output by the converter. Because ADC circuits take in an analog signal, which is continuously variable, and resolve it into one of many discrete steps, it is important to know how many of these steps there are in total. Resolution is very important in data acquisition systems (circuits designed to interpret and record physical measurements in electronic form). Another important consideration of ADC circuitry is its sample frequency, or conversion rate. This is simply the speed at which the converter outputs a new binary number. Like resolution, this consideration is linked to the specific application of the ADC.
In data acquisition terminology, the highest-frequency waveform that an ADC can theoretically capture is the so-called Nyquist frequency, equal to one-half of the ADC’s sample frequency. Therefore, if an ADC circuit has a sample frequency of 5000 Hz, the highest-frequency waveform it can successfully resolve will be the Nyquist frequency of 2500 Hz. If an ADC is subjected to an analog input signal whose frequency exceeds the Nyquist frequency for that ADC, the converter will output a digitized signal of falsely low frequency. This phenomenon is known as aliasing. The Nyquist frequency is an absolute maximum frequency limit for an ADC and does not represent the highest practical frequency measurable. To be safe, one shouldn’t expect an ADC to successfully resolve any frequency greater than one-fifth to one-tenth of its sample frequency. A practical means of preventing aliasing is to place a low-pass filter before the input of the ADC, to block any signal frequencies greater than the practical limit. This way, the ADC circuitry will be prevented from seeing any excessive frequencies and thus will not try to digitize them. It is generally considered better that such frequencies go unconverted than to have them be “aliased” and appear in the output as false signals. Yet another measure of ADC performance is something called step recovery. This is a measure of how quickly an ADC changes its output to match a large, sudden change in the analog input. In some converter technologies especially, step recovery is a serious limitation. An ideal ADC has a great many bits for very fine resolution, samples at lightning-fast speeds, and recovers from steps instantly. Different ADC technologies, though, have different strengths. Here is a summary of them ranked from best to worst: Resolution/complexity ratio: Single-slope integrating, dual-slope integrating, counter, tracking, successive approximation, flash. Speed: Flash, tracking, successive approximation, single-slope integrating & counter, dual-slope integrating. Step recovery: Flash, successive-approximation, single-slope integrating & counter, dual-slope integrating, tracking. Please bear in mind that the rankings of these different ADC technologies depend on other factors

1. Digital Storage (Memory) 12.1. Why digital? The advantages of the digital systems over the analog systems are the reproducibility of the results and accuracy; the ease of design (no special math skills needed to visualize the behavior of small digital logic circuits); the flexibility and functionality; the programmability; the speed (a digital logic element can produce an output in less than 10 nanoseconds) and the economy (due to the integration of millions of digital logic elements on a single miniature chip forming low cost integrated circuit (ICs). 12.2. Digital Memory Terms and Concepts data – stored information address – the location of the data

tracks and sectors – physical location of the data random access – to address quickly and precisely a specific data location within the device sequential access – the function of the random access is not possible here writing – storing a piece of data to a memory device reading – retrieving data from a memory device read-only memory (ROM) – pre-written memory device, that does not allow the writing of new data read-write memory – pre-written or blank memory device, that allows to be re- written volatile memory – an electric power is maintained to the circuit non-volatile memory – no source of power is needed to maintain data storage random access memory (RAM) – volatile electronic memory read-only memory (ROM) – non-volatile memory integrated circuit 12.3. Modern Nonmechanical Memory A very simple type of electronic memory is the bistable multivibrator. Capable of storing a single bit of data, it is volatile (requiring power to maintain its memory) and very fast. The D-latch is probably the simplest implementation of a bistable multivibrator for memory usage, the D input serving as the data “write” input, the Q output serving as the “read” output, and the enable input serving as the read/write control line:
If we desire more than one bit’s worth of storage, we’ll have to have many latches arranged in some kind of an array where we can selectively address which one (or which set) we’re reading from or writing to. Using a pair of tristate buffers, we can connect both the data write input and the data read output to a common data bus line, and enable those buffers to either connect the Q output to the data line (READ), connect the D input to the data line (WRITE), or keep both buffers in the High-Z state to disconnect D and Q from the data line (unaddressed mode). One memory “cell” would look like this, internally: When the address enable input is 0, both tristate buffers will be placed in high- Z mode, and the latch will be disconnected from the data input/output (bus) line. Only when the address enable input is active (1) will the latch be connected to the data bus. Every latch circuit, of course, will be enabled with a different “address enable” (AE) input line, which will come from a 1-of-n output decoder:
In the above circuit, 16 memory cells are individually addressed with a 4- bit binary code input into the decoder. If a cell is not addressed, it will be disconnected from the 1-bit data bus by its internal tristate buffers: consequently, data cannot be either written or read through the bus to or from that cell. Only the cell circuit that is addressed by the 4-bit decoder input will be accessible through the data bus. This simple memory circuit is random- access and volatile. Technically, it is known as static RAM. Its total memory capacity is 16 bits. Since it contains 16 addresses and has a data bus that is 1 bit wide, it would be designated as a 16 x 1 bit static RAM circuit. As you can see, it takes an incredible number of gates (and multiple transistors per gate) to construct a practical static RAM circuit. This makes the static RAM a relatively low-density device, with less capacity than most other types of RAM technology per unit IC chip space. Because each cell circuit consumes a certain amount of power, the overall power consumption for a large array of cells can be quite high. Early static RAM banks in personal computers consumed a fair amount of power and generated a lot of heat, too. CMOS IC technology has made it possible to lower the specific power consumption of static RAM circuits, but low storage density is still an issue. To address this, engineers
turned to the capacitor instead of the bistable multivibrator as a means of storing binary data. A tiny capacitor could serve as a memory cell, complete with a single MOSFET transistor for connecting it to the data bus for charging (writing a 1), discharging (writing a 0), or reading. Unfortunately, such tiny capacitors have very small capacitances, and their charge tends to “leak” away through any circuit impedances quite rapidly. To combat this tendency, engineers designed circuits internal to the RAM memory chip which would periodically read all cells and recharge (or “refresh”) the capacitors as needed. Although this added to the complexity of the circuit, it still required far less componentry than a RAM built of multivibrators. They called this type of memory circuit a dynamic RAM, because of its need of periodic refreshing. Recent advances in IC chip manufacturing have led to the introduction of flash memory, which works on a capacitive storage principle like the dynamic RAM but uses the insulated gate of a MOSFET as the capacitor itself. Before the advent of transistors (especially the MOSFET), engineers had to implement digital circuitry with gates constructed from vacuum tubes. The enormous comparative size and power consumption of a vacuum tube as compared to a transistor made memory circuits like static and dynamic RAM a practical impossibility. Other, rather ingenious, techniques to store digital data without the use of moving parts were developed. 12.4. Historical, Nonmechanical Memory Technologies Perhaps the most ingenious technique was that of the delay line. A delay line is any kind of device which delays the propagation of a pulse or wave signal. The delay line “stores” data on a very temporary basis if the signal is not strengthened periodically, but the very fact that it stores data at all is a phenomenon exploitable for memory technology. Early computer delay lines used long tubes filled with liquid mercury, which was used as the physical medium through which sound waves traveled along the length of the tube. An electrical/sound transducer was mounted at each end, one to create sound waves from electrical impulses, and the other to generate electrical impulses from sound waves. A stream of serial binary data was sent to the transmitting transducer as a voltage signal. The sequence of sound waves would travel from left to right through the mercury in the tube and be received by the transducer at the other end. The receiving transducer would receive the pulses in the same order as they were transmitted:
The next major advance in computer memory came when engineers turned to magnetic materials as a means of storing binary data. It was discovered that certain compounds of iron, namely “ferrite,” possessed hysteresis curves that were almost square: Shown on a graph with the strength of the applied magnetic field on the horizontal axis (field intensity), and the actual magnetization (orientation of electron spins in the ferrite material) on the vertical axis (flux density), ferrite won’t become magnetized one direction until the applied field exceeds a critical threshold value. Once that critical value is exceeded, the electrons in the ferrite “snap” into magnetic alignment and the ferrite becomes magnetized.
Jay Forrester of MIT applied this principle in inventing the magnetic “core” memory, which became the dominant computer memory technology during the 1970’s. A grid of wires, electrically insulated from one another, crossed through the center of many ferrite rings, each of which being called a “core.” As DC current moved through any wire from the power supply to ground, a circular magnetic field was generated around that energized wire. The resistor values were set so that the amount of current at the regulated power supply voltage would produce slightly more than 1/2 the critical magnetic field strength needed to magnetize any one of the ferrite rings. Therefore, if column #4 wire was energized, all the cores on that column would be subjected to the magnetic field from that one wire, but it would not be strong enough to change the magnetization of any of those cores. However, if column #4 wire and row #5 wire were both energized, the core at that intersection of column #4 and row #5 would be subjected to a sum of those two magnetic fields: a magnitude strong enough to “set” or “reset” the magnetization of that core. In other
words, each core was addressed by the intersection of row and column. The distinction between “set” and “reset” was the direction of the core’s magnetic polarity, and that bit value of data would be determined by the polarity of the voltages (with respect to ground) that the row and column wires would be energized with. The following photograph shows a core memory board from a Data General brand, “Nova” model computer, circa late 1960’s or early 1970’s. It had a total storage capacity of 4 kbytes. A ball-point pen is shown for size comparison: 12.5. Read-Only Memory (ROM) Read-only memory (ROM) is similar in design to static or dynamic RAM circuits, except that the “latching” mechanism is made for one-time (or limited) operation. The simplest type of ROM is that which uses tiny “fuses” which can be selectively blown or left alone to represent the two binary states. Obviously, once one of the little fuses is blown, it cannot be made whole again, so the writing of such ROM circuits is one-time only. Because it can be written (programmed) once, these circuits are sometimes referred to as PROMs (Programmable Read-Only Memory).
However, not all writing methods are as permanent as blown fuses. If a transistor latch can be made which is resettable only with significant effort, a memory device that’s something of a cross between a RAM and a ROM can be built. Such a device is given a rather oxymoronic name: the EPROM (Erasable Programmable Read-Only Memory). EPROMs come in two basic varieties: Electrically-erasable (EEPROM) and Ultraviolet-erasable (UV/EPROM). Both types of EPROMs use capacitive charge MOSFET devices to latch on or off. UV/EPROMs are “cleared” by long-term exposure to ultraviolet light. They are easy to identify: they have a transparent glass window which exposes the silicon chip material to light. Once programmed, you must cover that glass window with tape to prevent ambient light from degrading the data over time. EPROMs are often programmed using higher signal voltages than what is used during “read-only” mode. 12.6. Memory with moving parts: ‘’Drives’’ Modern disk drives use multiple platters made of hard material (hence the name, “hard drive”) with multiple read/write heads for every platter. The gap between the head and platter is much smaller than the diameter of a human hair. If the hermetically sealed environment inside a hard disk drive is contaminated with outside air, the hard drive will be rendered useless. Dust will lodge between the heads and the platters, causing damage to the surface of the media. Here is a hard drive with four platters, although the angle of the shot only allows viewing of the top platter. This unit is complete with drive motor, read/write heads, and associated electronics. It has a storage capacity of 340 Mbytes, and is about the same length as the ball-point pen shown in the previous photograph:
An incentive for digital data storage technology advancement was the advent of digitally encoded music. A joint venture between Sony and Phillips resulted in the release of the “compact audio disc” (CD) to the public in the late 1980’s. This technology is a read-only type, the media being a transparent plastic disc backed by a thin film of aluminum. Binary bits are encoded as pits in the plastic which vary the path length of a low-power laser beam. Data is read by the low-power laser (the beam of which can be focused more precisely than normal light) reflecting off the aluminum to a photocell receiver. The advantages of CDs over magnetic tape are legion. Being digital, the information is highly resistant to corruption. Being non-contact in operation, there is no wear incurred through playing. Being optical, they are immune to magnetic fields (which can easily corrupt data on magnetic tape or disks). It is possible to purchase CD “burner” drives which contain the high-power laser necessary to write to a blank disc. Following on the heels of the music industry, the video entertainment industry has leveraged the technology of optical storage with the introduction of the Digital Video Disc, or DVD. Using a similar-sized plastic disc as the music CD, a DVD employs closer spacing of pits to achieve much greater storage density. This increased density allows feature-length movies to be encoded on DVD media, complete with trivia information about the movie, director’s notes, and so on. Much effort is being directed toward the development of a practical read/write optical disc (CD-W). Success has been found in using chemical substances whose color may be changed through exposure to bright laser light, then “read” by lower-intensity light. These optical discs are immediately identified by their characteristically colored surfaces, as opposed to the silver-colored underside of a standard CD

1. Switches. Electromechanical Relays. Ladder Logic

6.1. Switch Types
A switch is a device that interrupts the flow of electrons in a circuit when pressed. They can switch between two states: completely on (‘’closed’’) or completely off (‘’open’’), which makes them similar to the binary devices. There are different types of switches, some simple, some more complex, but all of them have the ability to either be ‘’open’’ or ‘’closed’’.
6.1.1. Toggle Switches
The toggle switch can be found in most common households. They are actuated by a lever angled in one of two or more positions. Most used toggle switches will come to rest in any of their lever positions. There are also others that have an internal spring mechanism returning the lever to a certain normal position, allowing the so called ‘’momentary’’ operation.
6.1.2. Pushbutton Switches
Pushbutton switches are two-position devices actuated with a button that is pressed and released. Most pushbutton switches have an internal spring mechanism like the one mentioned above by the toggle switches. Others will stay in their ‘’pressed’’ position until the button is pressed again to go into the ‘’pulled out’’ position.
6.1.3. Selector Switches
Selector switches are actuated with a rotary knob or lever to select one of two or more positions. Like the toggle switch, selector switches can either rest in any of their positions or contain an internal spring mechanism for momentary operation.
6.1.4. Joystick Switches
A joystick switch is actuated by a lever free to move in more than one axis of motion. One or more of several switch contact mechanisms are used depending on which way the lever is pushed, and in some cases by how far it is pushed. Those types of switches are most commonly used for crane and robot control, sometimes even designed to be operated by the motion of a machine rather than by the hand of a human operator.
6.1.5. Limit Switches
The so-called limit switches are motion-operated switches. They are often used to limit the motion of a machine by turning off the actuating power to a component if it moves too far. These switches closely resemble rugged toggle or selector hand switched fitted with a lever pushed by a machine part.
6.1.6. Proximity Switches
Proximity switches sense the approach of a metallic machine part either by a magnetic or high-frequency electromagnetic field. Simple proximity switches use a permanent magnet to actuate a sealed switch mechanism whenever the machine part gets close (typically 1 inch or less). More complex proximity
switches work like a metal detector, energizing a coil of wire with a high- frequency current, and electronically monitoring the magnitude of that current. If a metallic part (not necessarily magnetic) gets close enough to the coil, the current will increase, and trip the monitoring circuit. Another form of proximity switch is the optical switch, comprised of a light source and photocell. Machine position is detected by either the interruption or reflection of a light beam.
6.1.7. Speed Switches
These switches sense the rotary speed of a shaft either by a centrifugal weight mechanism mounted on the shaft, or by some kind of non-contact detection of shaft motion such as optical or magnetic.
6.1.8. Pressure Switches
Gas or liquid pressure can be used to actuate a switch mechanism if that pressure is applied to a piston, diaphragm, or bellows, which converts pressure to mechanical force.
6.1.9. Temperature Switches
The temperature switches use a temperature-sensing mechanism called ‘’bimetallic strip’’, which is a thin strip of two metals, joined back-to-back, each metal having a different rate of thermal expansion. When the strip heats or cools, differing rates of thermal expansion between the two metals causes it to bend. The bending of the strip can then be used to actuate a switch contact
mechanism. Other temperature switches use a brass bulb filled with either a liquid or gas, with a tiny tube connecting the bulb to a pressure-sensing switch. As the bulb is heated, the gas or liquid expands, generating a pressure increase which then actuates the switch mechanism.
6.1.10. Liquid Level Switch
A floating object can be used to actuate a switch mechanism when the liquid level in a tank rises past a certain point. If the liquid is electrically conductive, the liquid itself can be used as a conductor to bridge between two metal probes inserted into the tank at the required depth. Level switches can also be designed to detect the level of solid materials such as wood chips, grain, coal, or animal feed in a storage silo, bin, or hopper.
6.1.11. Liquid Flow Switch
Inserted into a pipe, a flow switch will detect any gas or liquid flow rate more than a certain threshold, usually with a small paddle or vane which is pushed by the flow. Other flow switches are constructed as differential pressure switches, measuring the pressure drop across a restriction built into the pipe.
6.1.12. Nuclear Level Switch
Another type of level switch, suitable for liquid or solid material detection, is the nuclear switch. Composed of radioactive source material and a radiation detector, the two are mounted across the diameter of a storage vessel for either solid or liquid material. Any height of material beyond the level of the source/detector arrangement will attenuate the strength of radiation reaching the detector. This decrease in radiation at the detector can be used to trigger a
relay mechanism to provide a switch contact for measurement, alarm point, or even control of the vessel level. Source and detector are outside of the vessel, with no intrusion at all except the radiation flux itself. The radioactive sources used are weak and pose no immediate health threat to operations or maintenance personnel.
6.2. Switch Contact Design
One way to construct a switch is by bringing two conductors into contact with each other in a controlled environment and manner. A crude but easily understandable example will be two copper wires touching each other by the motion of a lever, or directly pushing two metal strips into contact. The conductive parts in a switch used to make and break the electrical connection are called contacts. They are typically made of silver or silver-cadmium alloy, whose conductive properties are not significantly compromised by surface corrosion or oxidation. Gold contacts exhibit the best corrosion resistance, but are limited in current-carrying capacity and may “cold weld” if brought together with high mechanical force. Whatever the choice of metal, the switch contacts are guided by a mechanism ensuring square and even contact, for maximum reliability and minimum resistance. Contacts such as these can be constructed to handle extremely large amounts of electric current, up to thousands of amps in some cases.
The limiting factors for switch contact ampacity are as follows: heat generated by current through metal contacts (while closed); sparking caused when contacts are opened or closed; the voltage across open switch contacts (potential of current jumping across the gap). 6.2.1. Mercury Switch A common type of sealed-contact switch is the mercury switch. Mercury is a metallic element, liquid at room temperature. Mercury switches use a slug of liquid mercury metal as a moving contact. Sealed in a glass tube, the mercury contact’s spark is sealed from the outside environment, making this type of switch ideally suited for atmospheres potentially harbouring explosive vapours. 6.2.2. Magnetic Reed Switches Reed switches are another type of sealed-contact device, contact being made by two thin metal “reeds” inside a glass tube, brought together by the influence of an external magnetic field. 6.3. Contact “Normal” State and Make/Break Sequence The normal state of a switch is that where it is unactuated. For process switches, this is the condition it’s in when sitting on a shelf, uninstalled. Therefore, contacts that are open in this position are called normally open and contacts that are closed – normally closed. Sometimes those terms are abbreviated to N.O. and N.C., respectively. Normally-open contacts are designated by the lines not touching, while normally-closed contacts are designated with a diagonal line bridging between the two lines. The switch on the left will close when actuated, and will be open while in the “normal” (unactuated) position. The switch on the right will open when actuated, and is closed in the “normal” (unactuated) position. Multiposition switches can be either break-before-make (most common) or make-before- break. The “poles” of a switch refers to the number of moving contacts, while the “throws” of a switch refers to the number of stationary contacts per moving contact.
6.4. Contact ‘’Bounce’’ Due to the mass of the moving contact of a switch and the possible elasticity inherent in the mechanism and/or contact materials, contacts will ‘’bounce’’ upon closing for some milliseconds before coming to a full rest and providing unbroken contact. Most of the times this presents no consequences, however, if the switch is used to send a signal to an electronic amplifier or some other circuit with a fast response time, contact bounce may produce very noticeable and undesired effects. For example, if we use a switch to provide a ‘’clock’ signal to a digital counter circuit, so that it increases the counted value with one every time the button is pushed. When the so called ‘’bouncing’’ happens, the circuit will mistakenly count a single push as several counts. Therefore, when we use switches for such precise work, we need to find a way to debounce them. There are several different ways of debouncing a switch contact: to reduce the kinetic energy of the moving contact, which will reduce the force of impact as it comes to rest on the stationary contact, thus minimizing bounce; to use “buffer springs” on the stationary contact(s) so that they are free to recoil and gently absorb the force of impact from the moving contact; to design the switch for “wiping” or “sliding” contact rather than direct impact, such as a “Knife” switch design; to dampen the switch mechanism’s movement using an air or oil “shock absorber” mechanism; to use sets of contacts in parallel with each other, each slightly different in mass or contact gap, so that when one is rebounding off the stationary contact, at least one of the others will still be in firm contact; to “wet” the contacts with liquid mercury in a sealed environment, so that after initial contact is made, the surface tension of the mercury will maintain circuit continuity even though the moving contact may bounce off the stationary contact several times. Each one of these suggestions sacrifices some aspect of switch performance for limited bounce, and so it is impractical to design all switches with limited contact bounce in mind. 6.5. Relay Construction Relays are extremely useful when we have a need to control a large amount of current and/or voltage with a small electrical signal. The relay coil which produces the magnetic field may only consume fractions of a watt of power, while the contacts closed or opened by that magnetic field may be able to conduct hundreds of times that amount of power to a load. In effect, a relay acts as a binary (on or off) amplifier. Just as with transistors, the relay’s ability
to control one electrical signal with another finds application in the construction of logic functions. In the above schematic, the relay’s coil is energized by the low-voltage (12 VDC) source, while the single-pole, single-throw (SPST) contact interrupts the high-voltage (480 VAC) circuit. 6.6. Contactors When a relay is used to switch a large amount of electrical power through its contacts, it is designated by a special name: contactor. Contactors typically have multiple contacts, and those contacts are usually (but not always) normally-open, so that power to the load is shut off when the coil is de- energized. Perhaps the most common industrial use for contactors is the control of electric motors.
Large electric motors can be protected from overcurrent damage through the use of overload heaters and overload contacts. If the series-connected heaters get too hot from excessive current, the normally-closed overload contact will open, de-energizing the contactor sending power to the motor.