So we all know about twisted-pair ethernet, huh? I get a little frustrated with a lot of histories of the topic, like the recent neil breen^w^wserial port video, because they often fail to address some obvious questions about the origin of twisted-pair network cabling. Well, I will fail to answer these as well, because the reality is that these answers have proven very difficult to track down.
↫ J. B. Crawford
The problems with nailing down an accurate history of the development of the various standards, ideas, concepts, and implementations of Ethernet and other, by now dead, network standards are their age, as well as the fact that their history is entangled with the even longer history of telephone wiring. The reasoning behind some of the choices made by engineers over the past more than 100 years of telephone technology aren’t always clear, and very difficult to retrace.
Crawford dives into some seriously old and fun history here, trying to piece together the origins of twisted pair the best he can. It’s a great read, as all of his writings are.
Crawford’s blog has been in my RSS feed for a long time already – it’s pure gold.
While we are at it, let me recommend Ken Shirriff’s blog. If you like Cameron Kaiser’s work, think an order of magnitude deeper reverse engineering stuff.
Pure token ring was so much better than regular ethernet that it was silly. Price and switched hubs changed the landscape for the better. And thank god i do not have to care about terminations any more.
The reason that Token Ring cost a lot more was because it was a lot more complex with the everything or most everything.
I laugh about your comment about terminations because yes, they were a bane in our existence because the people that initially wired for COAX and a different company later for twisted pair, hired the least expensive people that cared the least to do the connectors and terminators. I ended up replacing almost every single one of them as I realized that some of our network problems were because of the terminators and connectors were poorly crimped. I didn’t have time but then I COULDN’T __not__ replace them because of all the calls we were getting about network problems. My job title was as a programmer but that was only 25% of my job.
When the mainframe went away (see my other reply) we went from four people down to three and we supported about 350 people in the company with over 70 programs and 13 locations including headquarters and we were using modems to connect to our other sites from downtown or to downtown. There was no internet in our company until after I left in 1996. We didn’t get leased (always connected high speed – for the time) connections until about 1993…1994,
I worked at banks from 1983 through 1997. The bank I started at was a mortgage bank with 13 locations including our headquarters and then 12 HLCs (Home Loan Centers) where people went to fill out and sign paperwork to get a loan to buy a house).
When I started we had an HP 3000 mainframe with leased lines to all the HLCs (Home Loan Centers) where they had dumb terminals on everyone’s desk plus one (1) printer at each location.
We had an HP 3000 mainframe until late 1984 when our HP mainframe was sold and we were told there was a hard date six months from then when it would be gone. “All” we had to do was learn DOS and 3Com LAN Manager which was a modified version of Microsoft LAN Manager (garbage!) plus learn the C programming language then convert all of our COBOL programs to C. We also had to learn how to download all the changes from that days processing of mortgage loans to a file.
For anyone that knows the complexity of all the different types of mortgage loans, imagine having to learn a new programming language on a totally pretty new to the industry computer system (PCs with DOS) and pretty new PC Networks, both totally foreign to my boss and I, and we had to learn both PCs and the C programming language AND then convert everything over to PCs and have them in production six months later because the mainframe was leaving no matter what.
The top bosses hired contractors from West Virginia which produced code that was worthless as in it would have taken us more time to fix their code then to create the code ourselves because theirs had TONS of errors AND often the code all the different people looked and was written differently from each other. We didn’t have time to figure out all of their code and get it working.
Did I mention that there were only four of us in what was called “DP” or “data processing” at the time but is called “IT” now. Oh, and that one of them was our trainer that ONLY did training and didn’t know how to program. And another person ONLY knew how and only wanted to know how to operate the mainframe and that’s all they did.
So that means that there were only TWO of us that had to 1) learn DOS and 2) 3Com LAN Manager with 8086 PCs and 80186 servers and 3) learn C and covert about 70 programs from COBOL to C and 4) learn COAX ethernet cabling. Oh, and each night we had to download any changes to any of the mortgage loans at the HLCs AND at headquarters, the latter being where the Escrow department and other departments updated the files too and that had to be downloaded into separate files for each HLC.
Then each night we would have a computer next to my desk at headquarters dial up (call) each HLC and download the updates from that HLC and copy it to our computer at headquarters and then send any updates from headquarters out to the HLC with their specific file. Note that we had to learn how to create batch files which was a file with a list of command that would call each HLC, one at a time and upload/download updates or that HLC and then dial up the next HLC and so on until all 12 HLCs had their files uploaded/downloaded and then a program on each network would automatically upload all the updates that they received from the HLC or headquarters up into that servers database. And that had to be completed between 2 am (after backups were written to tape) and 8 am when people could log into their PC and start working. They were not allowed to login before 8 am to ALPS (our Automated Loan Processing System) that loan officers and their assistants entered all the information for people to get mortgage loans.
That, as I wrote it, was a very OVERLY simplified version of what we had to learn and do within six months and have it LIVE with no options for delays.
We started with COAX ethernet at each HLC and at headquarters. I no longer remember the distances but everything was done in series. All computers, as far as COAX ethernet was concerned, were in a line and the COAX cable (like you have for cable TV but on a different standard) was cut into pieces with ends crimped onto each end of the cable. Then either a T connector, which literally looked like the letter T, was used to connect to pieces of COAX cable together and then the third part of the T was connected to the PC. If the COAX cable with all the pieces that were connected together was longer than a certain distance then you needed a repeater which boosted the signal and extended it for added length.
If anyone of the connectors connecting the cable together was broken or taken apart the whole network stopped working. I’m not talking about the part that connected to the PCs but to the part that connected the pieces of the cable together. And we had to train people over and over NOT to disconnect it for ANY reason and we also ended up literally firing people because they wanted their computer on another corner of their desk and they would literally YANK the computer to try to “stretch” the cable. After three times of them doing this and bringing down the network and warned verbally and in writing they were fired. And it was amazing how many people had to be fired because of this. Which is why I’m mentioning this. We TRIED and TRIED to make them understand that you can NOT do this because it meant one of us (meaning my boss or I) had to stop learning or programming or whatever we were doing and had to rush to that site to figure out what happened and then phone someone to come in to fix the cable until we bought our own crimpers and started fixing the cable issues ourselves.
By the way, the person that hired the company that wired our networks paid them by the foot. And nobody from our bank stood and watched to make sure they didn’t do anything they shouldn’t have done like take several HUNDRED feet of COAX cable and literally wrap it around a water pipe in the ceiling where nobody could see it unless you happened to look in up under the ceiling tiles to see what they had done. I was the one that finally convinced the bosses to let us buy a device that could see the health of the cabling (the quality and the length of the wiring) and I realized that it was impossible for us to need that much length of cabling for a certain Home Loan Center (HLC). So over one night where I should have been sleeping I went there after hours and started removing ceiling panels until I found HUNDREDS of feet of cabling wrapped around a water pipe.
For anyone that doesn’t know what happens when you run water through a pipe, it creates an electrical current which degrades the quality of the signal running through COAX or twisted pair wiring if wrapped around said pipe.
I cut out the “extra” wiring and crimped new ends and used a connector like a T connector but without the third connect for the PC to connect the two ends together.
I then tested our network and we had DRAMATICALLY faster network traffic than we had before because 1) the segment on that part between the server and any repeater was now within specifications so the quality of the signal was no longer weak because of that, AND now because we didn’t have the coax cable wrapped around the water pipe anymore so the signal was better then too.
Note that the only time that a current forms in a water pipe is when water is running. Which means ONLY when water was running was the current created and therefore the signal on the COAX cable was diminished. So the network would slow down and possible stop during the time that a toilet was flushed or water was turned on at a sink and then it would better again. Suddenly that was never an issue anymore. But I had to go to all 12 HLCs and look through their ceilings and cut out all that extra cable we paid for but which was ruining our network traffic and then do the same thing at headquarters with the latter taking up two nights before a net cabling company was brought in to find all the extra cable at headquarters and yes, the executive who hired the cabling company was found to have stock in that company and he was also getting kickbacks and was fired.
Anyway … we were bought by a “national commercial bank” and we started moving from COAX ethernet to twisted pair ethernet. At some locations we changed all of the cabling at one time. At other locations for some unknown reason (well money) we only replaced some of the cable and not all of the cable so we had a mixed network of COAX and twisted pair ethernet. The weird part is that we had more than half of our HLCs running a mix of both instead of just 100% chasing HLCs from one to the other which would have been less complex and less costly. But again, upper management knew best.
With some of the HLCs (and downtown) we had two routers, one for COAX and one for twisted pair. At others we had routers which had daughter cards where each daughter card could be either COAX or twisted pair and you could change out one at a time, wiring another segment and then changing out the daughter card and then that segment was twisted pair while the other(s) were still COAX.
With this being a commercial bank we also had a network with a TOKEN RING network which is a LOT more secure than an ethernet network. As I understand it, each token knows which PC it is intended for and only that PC can decrypt the data. If the data isn’t for that PC or device (it could be for a printer or something else) then it just passes by and like a mail delivery person knows not to put your mail in your mailbox that isn’t for you.
Now we also had dumb routers and smart routers for ethernet. I’m not going to go into because that isn’t what this post (that I’m replying to) is all about.
The main thing for me is, I’m color blind. Or as I like to say it, I’m “shade challenged”. It isn’t that I don’t see colors. I just don’t see all the same “shades of colors” that non color blind people see. And by the way, a LOT of color blind people don’t know they are color blind. Because you can be just a little bit color blind and it never gives you any problems. And there are literally BILLIONS of not TRILLIONS of different degrees of color blindness. And that isn’t all.
I had a (different) boss (than my boss I described above) where the best colors for him on his computer was a yellow background and blue text. I’m not sure what colors he was color blind with but my color blindness is pretty common with red, green and brown looking like the same color but just different darknesses or shades of each other. And each different type of material from cloth to metal reflects colors differently so the exact same color on cotton will look different to me on sheet metal or traffic lights. Yes, traffic lights.
Now I can tell which part of traffic lights is lit so I have no problems because I know which light means stop, caution or go. But my mom’s dad, who was born in the 1800s and died in the 1960s, got a drivers license (somehow) and drove for several decades in Seattle where he built hundreds of houses north of the University of Washington. The way he approached traffic intersections in his car was to watch what other drivers were doing and do that. Or if he couldn’t tell what they were going to do or there wasn’t any traffic that he could __see__, he would either just drive through the intersection, push the accelerator down and hope for the best, or slow down until he could see whether or not cars were coming from another street where buildings or something was blocking his view until he could tell if it was safe to drive or not. Apparently he was in enough accidents or caused enough that they finally made him stop driving.
Why am I talking about color blindness or me being “Shade Challenged” as I like to call it? Well twisted pair wiring for PC networks has multiple wires and each wire is a different color. Cool, so it is easy to tell them apart? For a lot of people, the answer is “yes”. But for me the answer is absolutely “No”.
For me to run twisted pair wiring for either a phone or a computer meant that I had a 50/50 chance of wiring a phone, which only has two wires, 50% of the time. If it didn’t work then I switched the wires and re-crimped the end of the wire again and then it would work. But with four wires I had a lot less change of success and it took a lot longer for me to get it right.
Thankfully my job was a computer programmer. But, with me being in a PC part of “DP” or “IT” it meant that we ALL had to do everything. For the vast majority of running cable we hired a company to do it. We stumbled onto a company that did every kind of wiring for telephones and networks from PCs to mainframes for Boeing, that airplane manufacturing company that USED to be great but then top management that was 100% corrupt took over and … well that’s another story.
Anyway, this cabling company not only was great for us but they helped me too in helping me being better able to test both ends of the cabling by letting me borrow equipment for myself only for as long as I worked at that bank or they were our cabling contractor. The equipment they let me borrow let me connect a device to one end of the cable and then I would go to the other end it and it would tell me which wire was which cable and therefore I knew how to put the wires into the end connector and crimp it for those times when I had to fix something and it was much more cost effective (because it was less than a certain number or complexity or I just didn’t have time and I called them in). If I had time or I could do it quickly then I did it myself.
We also went from 1 MB ethernet to gigabyte ethernet for some of our networks but most were upgraded to 10/100 MB ethernet at the time I left the bank in 1996.
For anyone that has seen my posts in the past, my main job was as a programmer but when you work in a small company you have to wear multiple hats and other than management there wasn’t anything that I didn’t have to do for that small bank until we were swallowed up by a national bank and then a bigger national bank and so on.
Some people you KNOW will get the job done. I was one of those people that got things done and done correctly because I was lucky with programming and with wiring to learn from people that knew the right way to do things. It wasn’t always right from the beginning (with twisted pair ethernet) but eventually some company or someone came along to teach me the __correct__ way to do things or correct and smarter/faster ways of doing them. I would then pass on that information to others that I worked with and hoped they took the correct path.
If only I had people that could have helped me with my color blindness when I started working with twisted pair ethernet life would have been a LOT easier for me. Not only with cabling with actually quite a few things in life.
When you are color blind as a little kid and your teacher doesn’t know or thinks that color blindness isn’t real, and you are given fat crayons with no paper on them telling you what color they are, how are you to know which crayon to use when being told to draw an apple tree with grass around the bottom of them tree and a blue background.
As it turned out, the only color I got right was blue and maybe I had a red tree with green apples and brown grass or a green tree with red grass and brown apples or …
I knew my ABC and I knew how to read simple books for little kids. But I was shy and small for my age and I was shade challenged (color blind) and my teacher didn’t know or understand that it existed, that it was a “thing” or maybe she thought it wasn’t real. But because I was shy and bullied by both the kids in my class and my teacher because I didn’t know my colors I turned inward and really only partially re-emerged when by accident my second grade teacher saw some books when she took her own son to the eye doctor. These books told about color blindness and each of the pages had lots of color dots that made up circles and in each circle, if you weren’t color blind when they could see a number. And on some, if you were a certain type of color blind you saw a different number. Or maybe you didn’t see a number at all. And then at the back of the book it was the opposite. If you WERE colorblind then you DID see the numbers and if you weren’t you didn’t.
My teacher didn’t think there were any undiagnosed kids in the class with colorblindness. She just thought that it would be fun to spend a little time in class with her students looking at the colors and teaching about color blindness.
I turned out to be the only kid in her class that seemed confused by all of it. Because when she gave us the books she just told us to look in them and tell us what number they were seeing. Kids were calling out numbers, most the same number, maybe one or two saying a different number. Meanwhile I was just seeing colored dots making up a circle but I didn’t see any numbers at all or maybe I saw a number that nobody else said they saw.
Being already very, very, very shy there was no way I was going to raise my hand and saw that I couldn’t see any numbers. But thankfully that teacher, Mrs. Thompson, saw that I was shutting down, meaning I stopped looking at the pages and just closed my eyes and went into my own world.
Then she had me stay after class and she told me she KNEW I was color blind and that it wasn’t my fault that I couldn’t see the numbers. That it was a defect in my eyes.
You see, she had asked the eye doctor about those books in the waiting room and had asked if she could borrow enough for her students and she would bring them back in a couple of days. He said that is what they were there for and he happily not only supplied her with the books. But he taught her what to look out for with her students. To look for student that looked confused or any students that shutdown or just otherwise looked like they weren’t participating for some reason or another. He told her that there were MANY forms of color blindness. Literally as many as there were colors.
I remember VERY few teachers names but Mrs. Thompson is the one that I remember the most and most likely will be the one that I forget the last one I forget.
Most of the few that I remember are because of how negative they were with me or with my life. Like my electronics teacher who didn’t believe in color blindness until I proved that I was color blind. Resisters are color coded and you have to wire them in the correct direction or you get smoke when you connect power through the circuit. He thought I was cheating on the written portion of tests because I couldn’t create the physical circuits because my partner in class was rarely around (and flunked out of school) so I was left by myself and if I was lucky enough to get everything correct then things worked. But most often just one thing might be wrong and … smoke. Or multiple things would be wrong and … smoke.
But then most of the way through the year I finally convinced my teacher to sit down with me. I then described EXACTLY what I needed and which direction it needed to be (with resisters) and I soldered everything together and everyone of my physical assignments after that always worked as they were supposed to. What changed? I had someone who could see the colors handing me the right parts and when it mattered, in the right direction and then as I said, everything worked.
I also had him sit with me and ask me to create on paper circuits to do this or that, his choice and I had to write it out on paper and then do the physical circuit with him handing me the parts and he realized that I absolutely knew what I was doing and he regraded everything for my whole year. If I got it right on paper then he gave me a 100% on my physical part too. My grade when from a C- to D+ to an A.
Since he had never had someone he recognized as color blind before, he had never thought to think of ways to help someone like me overcome my inability to see colors correctly. I took that class as a junior in high school. Before I left as a senior he said he was now starting out every year with tests for colorblindness because as I told him, not everyone knows they are color blind. That way he can let the person know the struggles that they would have in class and in life with colors, as least as much as he understood them, and let them know how hard his class would be even if they completely understood how things worked on paper.
So the next time you see someone struggle with something due to colors, give them a break and understand that working with colors, no matter what that thing might be, including clothes or whatever, that person either knowingly or unknowingly is color blind and that life, when you don’t see colors the correct way, can be hard or discouraging or far worse.
As a little kid, by the time I was five, my earliest memories were bad ones where I wished I had never been born. As I grew older and became aware of what suicide was, well I OFTEN thought about suicide because I was bullied a lot because I was smaller, because I had to wear glasses, and just because one or more boys _could_ harass me or beat me up, they did. And nobody did anything about it.
The person next to you might be struggling with colors and might be struggling with reasons as to why NOT to commit suicide. I was on a razors edge my whole life until I met the first person that I ever felt REALLY cared about me. That person is my wife, whom I still married to.
I met her through my sister. Just briefly. Then five years later, two weeks before I was fired from a job along with everyone else where I worked (before the job that I started out talking about) because we got a new manager at a hot dog stand and she didn’t want ANY of the old staff no matter how good at their job they might have been. And I was VERY good at that job and loved it.
Like I said, I lived on a razors edge when it came to whether I kept living or committed suicide. Two weeks before I was fired my sister’s friend saw me and said hi and within those two weeks she asked me out on a date, which totally shocked me. And when I got fired very soon after, she reminded me that I had a two year certificate from a class that taught me how to program computers in COBOL, FORTRAN, RPG II, BASIC and other languages. And that is what I should be doing.
Two weeks before I graduated from that class there was a HUGE recession in the world and in where I lived and HUNDREDS if not thousands or programmers were laid off and the job that my teacher from my class had lined up for me vanished because they were able to hire someone with five years of programming experience for less than what they had agreed to pay me. And my teacher wasn’t able to find any other job for me and he said I was one of the best that had come out of his class in the last five years. That’s his words and that was just his class, not the world or even the region and maybe not within one square mile. I have no idea how I compared to anyone else. I just knew that I had to get __a__ job of ANY kind and I took a job with a company that had multiple brick and motor hot dog stands and I came VERY, VERY, VERY close to ending my life. I sat up many nights holding a knife to my wrist or against my chest debating whether or not to end my life.
About seven months later a very cute and smart woman, my sister’s friend, asked me out on a date and changed my life. Just to be clear, for something much, much, much better than my life had ever been before.
She had me get temp jobs, mostly in accounting because I was good with numbers. And that turned into jobs where I could use my computer skills to help make things easier for me.
With one job my boss realized that I could automate her department and if that happened then most of the staff wouldn’t be needed anymore and if you don’t know it, part of a manager’s pay is based on how many people ultimately are under them. That’s not always the case but more often than not it is. She could have gone from having 20 employees down to three or four and as I was a temp she quickly got rid of me before anyone in the company realized what I had told my boss I could do to automate her department.
Then I ended up at the bank as a temp. I won’t go into details but the loan accounting department was 100% manually doing everything without computers and there were about 20 actual employees with maybe 40 temps trying to help them. The previous manager had been fired two weeks before I arrived and the new manager was from outside the company and was trying to figure out how to fix that department that had a high error rate and was just a absolutely huge mess.
Two weeks later, once I had learned most of what I needed to help the person I that I hired as a temp to help, I realized that I could automate that job by computerizing it and I could easily write the program making it a one person or maybe two person instead of an eight person job.
I went to the manager and I told her what I could do. Then a short time later someone named “Bob” came to where I was working and talked to me about that. And then asked me to create a flow chart for what I was doing. I started and then asked how detailed he wanted it and he said as detailed as I could make it. He soon realized that I knew EXACTLY what I was talking about and I even started writing it out in COBOL to show him that I knew how to write it in COBOL which is what they used on their HP 3000 mainframe.
The next day I was given a mentor, a VERY intelligent woman who was in Mensa and had gone to MIT. She graduated near the top of her class but found she HATED the work that she was funneled to. Keep in mind that in the early 80s things were VERY sexist back then. Woman were “grudgingly” given jobs with the expectation that they would get pregnant and quit so they didn’t want to give them any job where they would expect you to stay in that job long term.
Anyway, she was my mentor and while she saw that I knew very well how to write the programs for my job and all the rest of that department if I just sat down with each person and had them explain to me everything they did on their job. And that’s what I ended up doing.
But what she did for me was explain math in ways that before that I had no understanding in. She has a PhD in math and chemistry. She could have been making a LOT of money somewhere else but was there at that bank as a programmer because that is the part of her job that she realized she liked doing. And this bank would NEVER ask her to do something she didn’t want to do. Or at least she didn’t think they would.
When our then manager of DP/IT left she was told she was going to be the next manager. She didn’t _want_ that job. She “just” wanted to be a programmer and wanted to stay being “only” a programmer. But they forced her into that job telling her that she was fired if she didn’t take it. She stayed for about a month, teaching me lot during that time that my math teachers in middle school and high school never came close to teaching me, and then she left to go work somewhere else as “just” a programmer. I would have followed her if I knew where she went. In the note she left for me she told me a lot of positive things about myself and her experience with me with her being my mentor.
They promoted another programmer in our group to be the new manager. Something I wouldn’t have wanted even if I had been right choice and I absolutely wouldn’t have been the right choice.
Weeks later, and I *think* they told my mentor that the bank was selling the mainframe and that was part of her reason for leaving. I think that because my new boss was told that same thing two weeks after he started as our manager and that the HP mainframe was going to be gone “no matter what” in six months.
Speed up a roller coaster that already feels like you are going to be thrown out at any moment and increase that by four or five and that is what it felt like for two years following the announcement that the mainframe was going away. That was my job as a programmer but I also was told that I was responsible for most of the hardware being setup and that all of the PCs had been delivered the the HLCs. I just had to set them up on the desks and then go back after the cabling was done. Meanwhile dumb terminals were also on those peoples’ desks and they didn’t want things to change. Oh boy did things change, including multiple times with the cabling over the eleven years that I worked for the bank(s).