Retro Edition: The LAN Before Time

Ethernet has been around since the mid-70s, but if you think it was always Cat5 and 10BaseT, you’d be sorely mistaken. The first ethernet was built with coaxial cable, vampire taps, AUI adapters, and a whole bunch of other network hardware that will make wizened networking veterans cringe. [Matt] had heard about these weird physical layers back when he started building networks in 1997, but he had never seen one. Now it’s an ancient and forgotten footnote in the history of computer networking. Is it possible to build a Thicknet in this modern era? It turns out, yes, it’s possible. It’s not easy, though.

The network [Matt] is building is a true 10Base5, or Thicknet, network. The backbone of this network is a coaxial cable 9.5mm in diameter. [Matt] discovered that while the common belief that Thicknet used RG-8/U cable. This appears to be incorrect, as the connectors for this cable – vampire taps that pierced the insulation and shield of the cable – are designed for cable manufactured by Belden, part number 9880.

[Matt] assembled the cable, vampire taps, AUI cables, and even found a few ISA NICs that would still work with a reasonably modern computer. He even went so far as to build a USB Ethernet adapter with an AUI interface. This impossibly retro device uses a standard USB to 10BaseT Ethernet adapter, with a chip designed to convert 10BaseT to AUI hacked onto a circuit board. That in itself is an incredible piece of engineering, with a handful of power supplies to get the correct 2.5, 3.3, 5, and 12 Volts to the right places.

As far as exercises in computing history go, [Matt] is at the top of his game. In the process of building it, he also figured out why no one uses Thicknet anymore; once it’s in place, you can’t change it, the cable is big, bulky, and the connectors are terrible. Still, it’s an amazing example of how far we’ve come.

58 thoughts on “Retro Edition: The LAN Before Time

  1. According to Metcalfe, the *original* 1 megabit Ethernet, at PARC, did use RG-8 cable, but when it was commercialized, a special cable was designed (yellow, not fire retardent, or orange, for use in air plenums), with two shields and slightly different characteristics. This cable still works fine as RF feedline, and will fit into PL-259 and type N connectors, if you want to try it.

    I designed the first Ethernet interface for Data General, using the Intel 82586 MAC chip. The AUI cables were almost as bad a design as IBM’s Token Ring cables – too large for the DB-15 connectors (whose slide latch was a poorly designed and ineffective abomination) and too stiff to allow easy routing. The vampire taps were finicky and destructive to the trunk cable. Our preference became the 3Com black box N-connector transceivers and crimped N-connector trunk cables.

    Aside from the physical shortcomings, Our thicknet Ethernet worked well. Of course, it wasn’t long until we had 10BASE-T and then switches…that worked MUCH better!


    1. The main reasons nobody uses thicknet any more:
      – mechanical ones
      – it’s a shared medium, one short or open takes down the whole network
      – you get much better throughput with switches

      // at one point, I had a spool of thicknet in my garage…long gone to the ham radio club.

    1. oooh, you evil evil man you! But yea I must admit me too.
      I had separate boxes of terminators, one box usually ordered but for making/modifying networks the normal way, and one box all taken from one end of a thicknet run from anywhere that the IT staff complained of being bored…

  2. Wait, are you suggesting that this is no longer required-understanding for “Network Essentials”? Dang I’m old. Granted, my understanding of thin/thick-net didn’t go too far, despite the books, as the vampire-tapping was being removed from my network in favor of 10baseT as soon as I got there… but dang, I certainly remember removing quite a few BNC T connectors and seeing piles of coax in the trash-bins… Nevermind the exams on the matter.

    1. I was fortunate enough to be at my university when they were pulling all the thicknet coax from the buildings and scrapping the sorts of machines that used AUI. Which, of course, led to frequent dumpster diving on my part. Thicknet was a non-starter at home, and decent hubs were still pricey (and switches moreso). Fortunately along with the RG8 cable they were scrapping the transceivers and AUI cables.

      Fun fact: 10base5 and 10base2 are electrically identical. So for each I soldered a panel mount BNC to the tap contacts, and hot glued it in place. Voila, almost free AUI-10base2 transceivers so the VAXen and Sun3s I collected could talk to each other.

    2. I still have numerous 10baseT AUI adapters hanging around I occasionally use outside of work without their nice expensive network testing gear.
      You can wire a 9-volt battery clip to a 15 pin DB connector (- to pin 6; + to pin 13) and you have the worlds most recycled link detector kit.
      Some even have activity LEDs to estimating broadcast traffic to determine how well your switches are actually switching.

      Sure beats plugging in an RJ45 wired up in cross over and running down to the switch to check the LEDs there if you have more than a couple ports to test.

  3. Um…. That box spare terminators isn’t useful anymore? Darn it…..

    I actually still use a switch with an N connector on it. The only thing the switch has ever seen on that connector is the terminator, though. Been in place about 15 years, and due for swapout whenever I get to it, if I do.

  4. Being a nerd/geek during the 90s I did install Thinnet 10BASE2 in my parents home, then shared apartments during highschool and later college, and those places saw many LAN weekends with 286, 386, 486 and later pentiums. But I also had a CD burner when it was new, and the blank CDs where about 25 USD each in bulk. Still have too many of those computors and network gear in storage.

    1. In the early ’90s I worked for a small firm with about 10 employees. Our offices (real rooms, not cubes) were wired for RS-232. When we finally got PCs/Xterminals, it was my job to wire up 10BASE2. When I asked my boss how I should route the cable he gave me a very large screwdriver and instructed me to poke holes in the sheetrock. Our LAN weekends consisted of xtank, then xpilot. Doom wasn’t out yet and only scaled to 4, plus we used X11 back then.

    1. Whatever you want! It’s usually RG-58 or comparable 50-ohm impedance cable. Good for cabling just about any analog or RF signal between the vast majority of equipment (excepting video-related like composite video, CATV, and AES/EBU which are usually 75-ohm). Even usable for wifi antennas, although there are better, lower-loss cable types for those applications (LMR-400 etc).

      The connectors are often not the highest quality, particularly screw-on and poorly-installed crimp types. So that might limit high-frequency or high-power applications above the frequency range of 10BASE2 (~20MHz).

      Seconding the ham club suggestion.

      1. That thin net cable is so lossy, at least in my experience. I am a ham myself, and I tried using some old RG-58 I had from when I pulled out my work’s thin net cabling and we pulled cat 5, and I was transmitting with a few watts on it, and the signal leaked so terribly out of the coax, I was better off using the rubber ducky antenna on my radio than an outdoor antenna connected with the coax. Perhaps it was just crappy cable, but it did have a foil layer, then braided wire for the shield.

        1. RG-58 is RG-58, within obvious construction differences. It is still used for interconnects on commercial 2way radio gear, albeit often quad shielded and at short distances.

          When abused and/or improperly terminated, all bets are off.

    2. Use it for pirating vhs tapes, some old vcrs use bnc connectors on them as well as f-type. All kidding aside thinnet stuff is worthless for transceiver patch leads, the center conductor is too brittle and breaks very easily. I used thicknet which was 75ohm rg11 for running 200watts through for a long time. It was very low loss, better than rg213 and on a par with lmr400 for signal loss.

    1. I have Lantastic install discs if anyone wants to try. It may not be compatible with Windows 10 though.

      On second thought, I’m also not sure anyone was keeping up with the license payments so the license may not be valid. :)

    2. Heh – as a 17 year old in 1996, I had the strange honor of being the IT firm I worked fors primary Novell Tech.. I had to take training and everything.. As they say in the military – sheeet rolls downhill.

  5. Quoted from the Hackaday text:
    > with a chip designed to convert 10BaseT to AUI

    Not that it really matters much, but I’d just like to point out that there is no 10BASE-T. The 10BASE-T PHY is not present in my design, and was removed from the proof of concept rig.

    It actually goes USB -> MII -> AUI

    Regardless, nice to see someone actually read this article, 3 years after I wrote it :P

  6. I miss ArcNet. Well, I guess I can’t miss it since I never used it but I was just ariving when my workplace at the time removed it. They gave me a bunch of ArcNet hubs. I really wanted to put them to use.

    What I liked about ArcNet is that it could be used in both Star and Bus configurations. Or.. a mix. You could use a hub with separate connections for each room with all the advantages of a star network but then daisy chain all the computers in that room so that you don’t need to run a whole bunch of wires.

    Also.. it used regular telephone wire. It was cheaper than Cat5 and Buildings were already wired for that!

    Top speed was 1Mb but my main purpose for a network was sharing internet. In those days I would have been floored to see a whole Mb of anything from the internet. The local network would not have been my bottleneck.

    I know people that actually worked with them complained about the terminators and one problem taking down the whole bus. I wasn’t too worried about that though.. crimping a resistor into a telephone plug is not exactly a challenge! Any rooms I would have wired with multiple computers would have had them on the same table too. Not too hard to just wire across a straight row. Odds were slim that for my use any two computers would see heavy use at the same time so I wasn’t too worried about the shared bus slowing me down.

    Alas… I only ever obtained a couple cards. They were both ISA. Even on Ebay ArcNet remained expensive. Ethernet dropped in price, increased in speed and I was finally able to wire up my own home with that. I kept the ArcNet hubs still for a few years thinking I might wire up my parents but then WiFi came down to their price range. I think I finally sold those hubs on Ebay or something never having used them.

      1. Lucky you! My first home network in the late 80’s was PLIP based (parallel port IP) using two AT&T 8088’s as routers/hubs to connect my four nodes, and to my hayes 2400 via serial.
        I used the onboard LPT1 on each to connect together the ‘routers’, and ports 2-3 on each for my four client PCs.

        I remember using a terminal to dial up the Greater Columbus FreeNET, navigating the menu options to drop to csh, launching slurp on the remote host, escaping out of my terminal and running slurp locally before enabling my NAT rule.
        After all that work I had the equivalent of a PPP connection (at least until mom picked up the phone)

        I’d spin around and fire up uucp on one PC to get my usenet and email spools sycned locally, then muck around various gopher sites until bedtime (still no WWW at that time, not until 92 or 93 or something)

        Anyone else remember spending hours trolling the public FTP looking for tiny grainy 8-bit porn gifs?
        And no not animated gifs, that’s just what we had in place of jpeg or now png. I didn’t go after MOVs until long after 36k modems, as transferring megabyte took around a half hour or so, and I could only store about 40 of them (megabytes)

        Come to think of it, they didn’t call it NAT back then (that was for those rich man routed networks) but something like IP Masquerading. Same basic thing as far as effect though. Hmm, no not iptables, not ipchains… ipfwadm!

        Man that takes me back.

        1. I fondly recall connecting my brothers computer to min with a 2 meter long LPT cable and using LPTlink for Age of Empires (the original one) and Half-Life 1 multiplayer 1on1 gaming. Good times.
          Windows 2000 Pro supported it out of the box and everything worked beautifully.
          No idea why we didn’t use ethernet and a hub, or even built a simple dumb hub, I would have been cable of that, given schematics.

  7. We had coaxial Ethernet at school. On RM Nimbuses, don’t laugh. Actually laugh, all the power of an 80186 at 5 times the price. Only school that didn’t have them in my area had a science teacher who understood PCs so he bought a load of 386s, probably for the same price. Ah, Research Machines, you big gougers!

    We didn’t bother with vampire taps though. Best not to use them if possible, there’s no need to. We just had T-pieces on each computer, with segments of cable in between each, cut to size. I think any empty plugs had a little terminator thing for continuity, maybe with a 50 ohm resistor in it. I think that terminated the network too, had to have stuff like that back in the day.

    I suppose it’s a novelty if you haven’t seen it. The bandwidth is crap though, and shared between all machines at once, a simple straight-line topology. Though since the machines probably had 512K of RAM they didn’t suck a lot of data, though none of them had hard drives, a couple had floppies, so they all booted off the net. Seemed quick. Will probably drive you mental doing anything modern with them.

  8. “Now it’s an ancient and forgotten footnote in the history of computer networking”
    – except it isn’t forgotten at all the industrial locations still using coaxial networks for all their old systems. :)

  9. Do I recall correctly hearing that the next intel chipset will go 10Gbit ethernet as standard?
    But actually even that seems rather lacking in futureproofness, they should really jump to 40 or 50 if that’s possible.

    1. I dunno that it is, they only invented Gigabit a few years ago, 10 gig is still rare in home user equipment. It’s also probably more than you need, but still, the future.

      How do they keep squeezing in this 10x increases? I know Shannon’s law, I don’t suppose they’re increasing the power output, although that would work, and since POE is supposed to carry 48V and be safe, no reason they couldn’t use that for signals as well. I know Cat 6 cable is getting more popular, but still, it’s just copper, there’s still a fair noise floor, especially with dozens of other gigabit signals racing round the motherboard, then a big chunky switching power supply not so far away.

      The constellation encoding AFAIK is as efficient as you can get, increasing speed just being a matter of putting more points on, if your chips get more sensitive, but still, noise floor.

      1. Infiniband have been 8gbps and up since early 2000 on copper. Not as far as ethernet, but tens of meters at least. According to wikipedia they are running silly-fast 290Gbps now, on 12x connections, I guess the 4x one is more comparable to ethernet, and the 4x infinband standard from 2005 is 16Gbps. A big thing with infiniband is the sub-micro second latency, a great fit for clusters.

        My point being, it’s a lot left in copper cables. even after 10Gbps.

      2. I think the basis for all speed increases is the transistors getting smaller and thus it becoming economical to make good cheap high frequency components/chips with ease, meaning you can use tricks that before were not possible.

  10. Whats fun is go back *before* ethernet.. there was Arcnet, somewhat like the later ethernet “thin-net”, with bncs and terminators.. The first network I set up, back in 1987, was Arcnet, and a Novell 2.X server. It ran on a Compaq Deskpro desktop, Intel 80286 cpu and 64MB of ram, and a 300Mb ESDI drive… Oh those were the days..

    1. The Intel 80286 CPU used a 24-bit addressing scheme. Each memory location was byte-addressable. This results in a total addressable space of 224 × 1 byte = 16,777,216 bytes or 16 megabytes. Actually owned one with windows 286 and 16mb ram.

  11. All these people reminiscing about the olden days, and then here I am.
    My first computer that I owned myself (Not counting the family computers) was an old Pentium 4 that I picked up in ’09 after my school got rid of it. Jesus, I feel so young in comparison.

    1. Ah, it’s only the 1980s. I used to read alt.folklore.computers on Usenet. Denis Ritchie posted there. They reminisce about punch cards, teletypes, and mainframes with 8K of magnetic core RAM. When IBM would lease them out for silly amounts of money. I haven’t read it much since Usenet died, and I’m kinda worried that Usenet’s not the only thing not to last this far into the 21st Century. Great old characters with great stories, and you can learn some stuff from back when the things you use now were first invented.

      Still doubt the “death” of Usenet mattered much to that group, many of them having been on it since Internet sites were named the other way round.

  12. Reminds me of ARCNET and “Star Topologies.” Every machine had a node and was either hooked up to a hub on a Novell machine (486DX2/66) and had a “node address.” That, along with Token Ring really brings back memories and the horror of older networks. :)

  13. I still remember all of the coaxial cable that we put into the (drop) ceiling of my floor in residence back in the 90s to connect all of our computers together on Ethernet so that we could play multiplayer DOOM. I bet it’s still there!

    1. I’ve only really heard of a TDR mainly for finding cable techs finding illegal cable TV taps. A college electromagnetism prof was relaying an anecdote about someone in his neighborhood being surprised at how quickly the local cable company found his connection.

  14. I remember in the 80s I bought some coax and MAUs from ‘black-box’ to connect two SUN 386i workstations. I didn’t even know they needed terminators (I should have, having done transmission line theory at college), It took me days to find out why it didn’t work. No google search back then. :(

  15. Very nice! Brings back memories of my first lan. Took surplus thin net adapters, scrounged some T taps, had only seen the terminators and didn’t know what was in them. Used 75ohm cable and got two computers in my house wired. It didn’t work of course but I did figure the terminators were resistors similar to video distribution amp dummy loads so I took one I had and a variable pot. Fired up icmp and started trying to pass traffic. Started to mess with the pot till I saw responses. Bingo. Measured the pot and got a resistor out of my kit that matched. Not bad for a high school kid that didn’t have any help except a few library books and a vague idea.

  16. Doesn’t seem that long ago I had a few machines sharing dial up internet connection with over coax.

    Still have some 10Base2 stuff laying around, a hub with bnc connector for bridging to twisted pair, cables, Ts, terminators, in case I feel bit nostalgic and want to connect a few machines up. Takes just a few minutes to have everything up and running. It’s easy enough to get old Dos machines doing irc or transferig files using it.

  17. In the early 90’s I was working for a company that were the last tenants of a 20-30 year old single story building that was being demolished for a 20 story building. We had access to the whole building (and any left over equipment). I went to remove some network cable from the drop ceiling. When I finally found a panel that I could push up I found a foot thick layer of cables from just about every network ever conceived!Thicknet, DECnet, token, RG58, RG59 and 93ohm coax. Whenever a new network was installed it was layed on top of the old stuff in layer after layer. I was amazed the whole mess had not collapsed on our heads!

    1. BNC-T’s are useful for making measurements. Along with the terminators you can terminate coax to 50ohms at oscilloscope input. They also work for splitting RF signals if you are a dirty amateur who does not are that much about impedance’s and reflections.

  18. whippersnappers today dont even know how good they have. _single collision domain_ explains horrors of the past, imagine whole company network run over one wifi channel. Alternative was expensive token ring (guaranteed time slots).
    Jumping over to twisted pair ethernet made life easier for technicians/installers, and switches provided final quality bump (no collisions).

  19. Wow…as someone whose first jobs involved punch cards and mainframes, I can remember how impressed everyone was when I setup the first Novell network for the secretaries in IT. Back when I had lots more hair, idealism, and energy. What would Young Blodgar have thought of these tiny android TV boxes with quad-core 2 Ghz processors? Probably the same thing I do today – “I’m strapping two of these babies on my telescope!”

  20. I used to install 10base5 as a teenager. Before that I helped my dad install Wang duplex cabling on the weekends.

    We even installed a ThinNet network in our house, connecting my upstairs bedroom to his office out in the garage (with an underground plastic conduit connecting the two structures).

  21. Oh SWEET, now I can make USB connected versions of classic 10GHz and 24GHz microwave links!
    Like this one
    They used AUI for the connectivity because it existed and did not care too much for the stuff connected.

    Now I’ll just have to save a couple of the older AUI equiped NIC’s and switches for building equipment at one end and put those Gunnplexers to some real use!

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