The TRS-80 model 100 goes online

Sometimes added functionality isn’t exactly functional. Sometimes, it’s more a sort of demonstration that something can be done, whether or not it’s actually a very good idea.

UK readers may not recognise the machine below, but those of you in the USA (as long as you’re of a certain vintage) will be familiar with it. It’s a TRS-80 model 100: an incredibly early (1983-ish) laptop-type computer, whose market was mostly in the US and Canada, made in partnership by Kyocera and Microsoft. The 8k version would set you back $1099, and the 24k version $1399 – an absolute ton of money in 1983, when we many of us at Pi Towers were either not born yet, or still at the corduroy dungarees and deelyboppers phase.


The TRS-80, rather amazingly, was a connected machine, with a built-in modem. It was a popular tool for journalists; you could save about eleven pages of text if you were out in the field, and send it over that modem to your editor using a program called TELCOM – an incredibly liberating technology at the time. It was pretty power-efficient as well; it took four AA batteries, which lasted for about 20 hours.

So what better for retro-hardware lovers than an internet-connected TRS-80 model 100? That’s exactly what Sean Gallagher from Ars Technica made.


I successfully logged in to Ars’ editorial IRC channel from the Model 100. And seeing as this machine first saw the market in 1983, it took a substantial amount of help: a Raspberry Pi, a little bit of BASIC code, and a hidden file from the website of a certain Eric S. Raymond.

Sean says that the TRS-80 is the last machine Bill Gates ever wrote a significant amount of code for, and that Gates has said it’s his favourite ever machine.

This is a really tricky problem to work your way around when you consider that modern websites don’t really work within a 40 columns by eight lines display; that the TRS-80 keyboard doesn’t have a | or pipe symbol; that you can’t load a TCP/IP stack onto the device; that Sean had to build his own null-modem cable – it’s a labour of love and an absolutely fascinating read. Head over to Ars Technica to read more about dragging 1980s hardware some of the way into the 21st century.



Zak Zebrowski avatar

I used to have a device (similar to this, but a slightly different vintage), in 1994-ish so that I could have a laptop in high school. It was awesome for taking notes while in high school and college, and printed straight to an apple imagewriter ii printer. Very cool hack!

Jeff Findley avatar

This sort of thing would work with just about any old computer with a serial port and a terminal program. I used to log into my university account on my C-64 at a whopping 1200 baud using a program which emulated a VT-100 terminal. It worked great for checking my email from my dorm room.

Liz Upton avatar

That tiny display’s the real constraint here, of course; we’ve all been talking about how we’d get around it. I don’t think any of us has come up with a very elegant solution yet!

ukscone avatar

the m102 was my main internet email (and bbs machine) for quite a while in the early 90s. you’d often see me in a phone booth looking shifty. the 40×8 was fine for those functions. there is a mod somewhere that iirc gives about 50 to 60 characters per line

Tony in Australia avatar

I used an M100 as a portable interface in the early 80’s to program industrial controllers (PLCs). Trying to view hundreds of lines of PLC ladder logic code peering through a via a 4 line display was a real challenge (an 80 character PLC would line wrap and take up two lines of the M100).

I solved this by taking to site a box of perforated edge continuous A4 computer paper and an Epsom tractor feed printer.

Problem Solved, a high contrast large scale display.

Elegance using 80’s technology!!!!

andrum99 avatar

I remember coming across an old TRS-80 Model II in a cupboard at school (here in the UK) and being amazed by the huge size of the floppy disks – 8 inch floppy drives it had – the same physical design as 5.25 inch disks only a bit bigger!

Tobias K avatar

I have a few 8″ floppy disks I kept for nostalgic reasons, and also so I can demonstrate why they were named “floppy disks” in the first place. :-)

Liz Upton avatar

They’ve got a bad habit of growing mould – I’ve had some very interesting conversations with the folks from the Computing History museum in Cambridge about recovering data (and sometimes failing to) from floppies with horrible bloom growing on the magnetic medium!

Tobias K avatar

Really, mould? Most interesting, Liz. That probably explains at least part of my state of mind… Luckily, it’s extremely dry here, so I bet they still work.

Andrew Reeves avatar

Great now I have this urge to check my old 5.25 floppies for mold. Plus I learned that mould is another one of those words us crazy Americans dropped the u on.

whheydt avatar

Oh, my…that brings back memories….

My wife had an M100. Not only did we add the extra 16K memory, but she had an add-in module that allowed attaching an external (after market) 3.5″ floppy drive.

A bit later, I got a M102 to use for myself.

I went so far as to work up a termcap entry for the M10 and M102, and submitted it to the folks maintaining bsd unix. It got added to the database and it’s probably still there on any system using termcap. Alas, not true of Raspbian, but it’s possible that the terminfo contains the same descriptors, as AT&T derived terminfo from termcap.

Russell Barnes avatar

Love it. That’s got to go in the magazine!

ukscone avatar

My 1st real paycheque in 1985 was spent on an M102 with 24k & an acoustic coupler and some odds and sods left me with no change from about 1200 quid. it was in continous daily use until 2007ish when someone with great big clodhoppers stepped on it. it’d had been to greece, france, the netherland, gemany the states and back a few times, was my main machine on my leicester to london commute for a year & was covered in stickers & mods. it’s since been replaced and I use it and VirtualT on a raspberry pi at least a couple of times a week. game of snake anyone?

wallyware avatar

We called them the “Trash-80″s. They had to compete with the Atari 800 and the Commodore 64.

ukscone avatar

i’m a TRaSh-80 fanboi. we had model 3’s at college and i’d hang at the Leicester Tandy computer store every chance I got. Many hours wasted in my youth playing Big-5 games and general faffing around on Tandy’s. IMHO they are the last computer that “looked” like a real computer :)

Andrew Gale avatar

You can still get Amstrad NC100s on eBay quite cheaply and they’ve got a serial port and an 80×8 character display which could work nicely! Oh…. and they’ve got BBC BASIC on board, too!

ukscone avatar

my nc100 has a cracked lcd (and probably very manky now anyway). I did look for a replacement lcd on ( ) but I never got a reply to my email query about 5 years ago so gave up on fixing it for the time being. it’d be nice to fix it one day as there is a unix-like os for it which was fun while my nc100 worked

jay avatar

Should I break out my old KIM’s with 1K KIM-SI bus? and use a rPi to connect??

Jeff Greer avatar

I had one of the originals with quite a bit of expansion. I still have three of them including a Model 200. It was cutting edge at the time. The files were all displayed on the screen. When you selected a file, it automatically came up with the proper application. The modem in those days in conjunction with Compuseve was very slow. You could actually read the messages as they came in, in real time. I still remember my CIS account number: 70035,1412. Compuserve cost $6 per hour back then. Also a lot of money, particularly at 300/1200/2400 baud. Tapcis helped with that. You could do your editing and reading off line.

It was a heady time.

Maybe I’ll relate running a Unix clone called Coherent on an 80386 Zeos laptop, someday (pre Linux). I’m sure I was one of the first to get “unix” running on a laptop. It beat having to wait in line for one of four terminal connected to a Sequent computer in the university lab.


apemberton avatar

I was the proud owner of one of an M102 which was so useful as a field tool working on telecoms kit. I bought one as my company couldn’t justify or supply such an amateur piece of kit for their workers. So useful for capturing teletype sessions for later analysis, making scripts for testing saving innumerable keystrokes etc. I was envied by my colleagues for a short while. Never did get on with clattering ASR33’s or KSR28’s for telegraph use!
Mind you, my home computer was a home-brew Z80 CP/M system (I built the modules using stripboard and wire wrap – I still have them – god knows how much Lead/Tin solder I handled and flux fumes on my lungs!) with 8″ floppies and an eprom programmer.
I miss the days of ‘real’ computers and cannot get on with tablets or other playthings (e.g. W10) so I am soooo glad that the Rpi is around to keep my hand in on experimentation although with such a range of modules available, not much soldering is needed and software is such good clean fun!

Neil avatar

And the only remaining question is: Why? Just for the reminiscing, yah? Or is it because it’s among the few things our failing minds can remember? I have owned (and designed, and built) a number of machines of that era. Compared with a Raspberry Pi, they were all rubbish.

Mike Cook avatar

All of the early Body Build articles were written on a TRS80 model 1 before I changed to a Mac in 1985. I had a friend visit the states and got him to bring me one back in 77. Just a keyboard. I added a video monitor home made power supply, floppy disc drive, 16K memory extension and multi I/O card including a sound chip. I also did the mod to give lower case characters because it was upper case only. The print function had a vector associated with it and I hijacked that vector to redirect the print statements to a driver for a mechanical teleprinter for hard copy. In the first issue of The Micro User mine was the only copy actually written on a computer.

Liz Upton avatar

The more I learn about you, Mike, the more hero-worshipful I get. :D

Mark Barnett avatar

I have a Model 102 and it is an awesome device. If it had a USB port on it I would use it tomorrow. It runs ALL day on a couple of rechargeable batteries. Everything is text based, but I wouldn’t mind it for MANY tasks, like email. The keyboard is solid and feels WAY better than the computer I’m typing on now.. It has NEVER crashed and is FAST!

Niall Saunders avatar

In the closing years of the ’80s, I started using the PSION hand-held computer. Again, a very simple text-based multi-line display – but this time there was reasonably decent solid-state memory. It looked like a brick, felt like a brick and was built like a brick.
A remarkable little device – the ‘smart tablet’ of it’s era!

Gravesy avatar

This reminds me of the 7th part of “BBS: the documentary” :
Similar type of project and (to me, at least) a great piece of nostalgia.

Jonathan avatar

I just set my B+ up with Arch Linux and connected to a Model 100 at 9600 baud. I used the built-in serial port on the GPIO and an external level-shifter based on the MAX232N chip (C019). I made my own null-modem cable between the DB25 on the model 100 and C019. I changed the baud rate for /dev/ttyAMA0 to 9600 on Arch and enabled software handshaking on the 100. Arch seemed to have xon/xoff by default.

Next step is compiling desklink….

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