How do I Connect a 30yr-old Tandy 1400LT laptop to the internet?

Just for the fun of it, I want to get an old Tandy 1400LT laptop:

NEC V20 (Intel 8088 equivalent)
640 KB RAM
9'' CGA backlit monochrome display
two 3,5'' 720KB DD floppy drives
RS-232C serial port (DB-9 M)
Centronics port parallel (DB-25 F)

enter image description here

I want to connect the thing to the internet and use it as an SSH terminal.

The OS should be no problem as it is a 386 hardware. There should be a small Linux distribution which can be run on it.

The problem I see here is the internet connection. Does anyone have experience with serial/parallel-to-Ethernet converters?

Clemens Bergmann

Posted 2014-05-28T16:37:18.170

Reputation: 711

I've got one of these. Would you mind taking a picture of the motherboard? I removed the CPU and can't remember which of the two sockets it was in. – Wyatt8740 – 2014-09-28T00:51:29.067

This is more of a "I did this" vs answer. I have a 1400LT upstairs. Back in the day, maybe 1992-94 I used a homemade cable to connect the 1400LT to another computer using a null modem cable and "LapLink" or something similarly named. Basically changed the A/B drive to G/H drive on another machine. Never did anything else w/ it. My 1400LT doesn't have any "modem" and at the time dial-up was all we had. I nearly threw away the last dial-up modem I used the other day (Nov 2014). Something inside made me keep it, thinking why throw away a perfectly usable electronic item... – None – 2015-01-24T22:41:40.230

According to the very page you linked, its processor is not a 386, but a NEC V20 (Intel 8088 equivalent). The LT model also has no HDD, so you would need a PC-XT compatible linux, with TCP/IP stack, that runs from a floppy.

– That Brazilian Guy – 2014-05-28T17:07:55.560

25Get a serial modem and use dial-up. – Ƭᴇcʜιᴇ007 – 2014-05-28T17:08:09.637

Even if it would have been a 386, support for 386 was dropped from Linux, so you'd have to run an old version.

– Cristian Ciupitu – 2014-05-28T20:06:59.993

You might be able to modify ELKS to run on it – PlasmaHH – 2014-05-28T20:11:41.883

How about using an older version of Minix? – thkala – 2014-05-28T20:12:12.103

Even FreeDOS needs at least an Intel '386 or better processor.

– Cristian Ciupitu – 2014-05-28T20:14:12.307

1What about an acoustic coupler modem? Still limited to 1200 baud, but will work with the RS-232c. – JohnP – 2014-05-28T20:51:02.937

Does anyone else find the phrasing w.r.t. the RAM available rather suspicious? "640 KB + 128 KB available for RAM-based disk driver or print spooler" seems to indicate that those 128KB may not be directly addressable by the processor... – thkala – 2014-05-28T21:53:52.387

@thkala Might be mapped above 1 MiB to allow for 640 KiB conventional memory plus the 384 KiB hardware address space of the IBM PC/5150 design? Page switching was a common technique back in the days. Think EMS. – a CVn – 2014-05-28T22:40:04.093

You could use an Arduino hooked to the serial port to "translate" the Ethernet packets into some serial data to read from Tandy. But you will have to write custom code... – NothingsImpossible – 2014-05-29T12:42:58.337

@thkala it probably just means the computer has 768k total ram. Standard DOS programs were limited to 640k of ram, with the space between 640k and 1024k available for use by driver type programs (TSRs). – Dan is Fiddling by Firelight – 2014-05-29T13:40:27.120

A word of caution. These old devices are a fire hazard. Don't run it unsupervised. – Peter - Reinstate Monica – 2014-06-01T15:13:20.983

Answers

The OS should be no problem as it is a 386 hardware.

You'll probably need 4MB of RAM (likely higher) at an absolute minimum to run Linux, and likely 16MB to run any distribution or kernel with a decent software selection since 2000 or so. If you can't upgrade the RAM you are stuck.

Some brief searches seem to suggest this has an 8088 with 512KB or 768KB or RAM, though. Modern Linux won't run on that at all. (You may want to keep an eye on ELKS, the Tandy's NEC CPU is mentioned in the boot/setup.S file.)

I did get Linux booted on an old 1995-era "Winbook" laptop via floppy, I believe I used muLinux.

rs-232c connector

The way to "convert" serial to a network connection is PPP. You would need to set up a PPP client on your laptop, and have a pppd running on another Linux/Windows host that can route your ppp connection to your outgoing Internet connection.

You can probably still use it as an ssh terminal somehow if you install SSHDOS on it.

If anything, put an RS-232 adapter on your Linux system, configure your inittab to spawn a getty on ttyS0 or ttyUSB0 and use a DOS terminal program to access your system.

LawrenceC

Posted 2014-05-28T16:37:18.170

Reputation: 63 487

thanks, you make a very good point with the RAM problem. I will try to first solve the software problem. I think the sshdos variant could be a good option. If that works I can then think about the connectivity. – Clemens Bergmann – 2014-05-28T19:55:09.463

4One Option might also be to use a actual 56K modem that I have here and do a real dialup-connection to a ISP. I have read that some providers provide free-of-charge dailup connections. That would be the most "matching" sollution. – Clemens Bergmann – 2014-05-28T20:06:57.410

Unfortunately, this machine will never have 4MB. At most, he can find 768k – eyoung100 – 2014-05-28T20:15:08.887

Freedos might just run on it (http://www.freedos.org/), 2MB or more RAM for optimal performance, but 768K should probably work alright. Not sure about the HD size though. Freedos has an ssh client as well (http://www.freedos.org/software/?prog=ssh2dos).

– MaQleod – 2014-05-28T20:29:55.467

@MaQleod, even FreeDOS needs at least an Intel '386 or better processor. – Cristian Ciupitu – 2014-05-28T20:33:01.620

2@CristianCiupitu No, FreeDOS should be fine with an 8088/8086 compatible. See my comment on the question proper. – a CVn – 2014-05-28T21:13:21.993

2@ClemensBergmann I really doubt that machine will be able to keep up with a 56 kbit/s data stream on the serial port. Considering that it's from long before 16550 UARTs became common, it'll have an 8550 UART at best, which will be a serious bottleneck for high-speed serial port communications. – a CVn – 2014-05-28T21:14:27.037

6I believe the CPU is too slow for anything involving encryption to be usable. – Thorbjørn Ravn Andersen – 2014-05-29T14:43:18.873

@ClemensBergmann Here is a Hackaday article about installing Linux on an old laptop with a 25MHz CPU and 4MB RAM (which the author does successfully): http://hackaday.com/2011/08/12/installing-linux-on-a-386-laptop/ Probably a good starting point if you want to go the Linux route.

– Jason C – 2014-05-30T06:14:20.057

You may also want to have a look at OpenEmbedded (http://www.openembedded.org/wiki/Main_Page) and talk to the community there. It's primary purpose is Linux on highly resource-limited embedded systems (e.g. microcontrollers), and the performance of this laptop is on par with low-end microcontrollers; it might be a more feasible approach.

– Jason C – 2014-05-30T06:18:46.697

1I'd use SLIP rather than PPP. Easier to set up. And if I feel particularly adventurous and speed hungry, PLIP. – Simon Richter – 2014-05-30T11:40:10.053

You could use a Rasperberry PI to do the PPP and SSL etc and plug the ethernet into the PI and the Tandy into the PI. That'll make it more into a dumb terminal. Might even be able to case-mod the Tandy to internalise the PI board. – Sled – 2014-05-30T15:58:06.140

Google results for ELKS take you to the abandoned and crumbling sourceforge site. The new hotness (or at least, the not old and busted) is at the ELKS github site.

– Scott Leadley – 2014-06-02T14:40:42.027

Well, if you're really feeling old-school, you can go back to a prehistory I'm barely old enough to remember!

You will need:

A copy of DOS to run on the Tandy
Kermit (the terminal emulator, not the frog)
A null modem cable (or for some real old-school cred, a couple of dial-up modems & phone lines)
A machine running some kind of Unix-like OS, connected to the internet, with a serial port.

Configure the Unix machine's getty or eqiuvalent so you can log in on the serial console.

Connect the Tandy to the Unix machine's serial port.
Either using the null modem cable or via the two modems and the telephone network.

Fire up the terminal emulator.

Dial the modem if required.

Use links (or lynx), ftp, PINE, or any other favorite text-mode internet software.

For best results watch this while setting it all up.

voretaq7

Posted 2014-05-28T16:37:18.170

Reputation: 2 051

4Yes, we really did live like this once. For my first few years on the Internet with a Windows box you'd have the dial-up connection open a terminal window after it dialed the number so you could log in to the server and type ppp at the shell prompt. Then you'd close the terminal and let Windows proceed to negotiate the PPP connection. All so my high-tech Netscape 3.x browser could render frames and tables. – voretaq7 – 2014-05-28T21:15:53.397

What no mention of gopher or nntp reader like tin?

– Zoredache – 2014-05-28T21:43:10.710

PINE > tin! If you know of a reasonable entry into the Gopher tunnels these days I'd be quite happy to include that though... – voretaq7 – 2014-05-28T22:03:17.410

+1: I think this has the best chance of actually working without becoming an entire time sink. – copper.hat – 2014-05-28T22:59:07.323

2+1 It should be noted, though, that this just turns the Tandy into a relatively dumb serial terminal. It would work, of course, but you might just be able to do a little more with it... – thkala – 2014-05-29T06:43:58.357

This is the right answer. The machine is just barely powerful enough to run a terminal emulator - forget everything about running ssh on it. – Thorbjørn Ravn Andersen – 2014-05-29T14:38:27.837

@ThorbjørnRavnAndersen: maybe not SSH, but a network stack with a telnet client might just be possible. After all, this question is probably more about the possibilities... – thkala – 2014-05-29T15:35:00.453

Oh you could probably rig something up to get the thing talking SSH if you're really determined (might involve some creative program overlay techniques though) - Machines like this make great portable terminal emulators though, and you can always use a serial console for SOMETHING :-) – voretaq7 – 2014-05-29T15:41:22.943

2@thkala I am old enough to have actually done this many moons ago, as well as connect a 8088 machine (which is very close to this V20) to the Internet using a net card under MS-DOS. MS-Kermit was usable with a single telnet session, but for multiple sessions it was too slow. I believe the user ended up using NCSA Telnet. – Thorbjørn Ravn Andersen – 2014-05-29T15:51:30.843

"Kermit (the terminal emulator, not the frog)" - Aww... But I like the frog... – haneefmubarak – 2014-06-01T00:24:16.973

I have a 1400HD and oddly enough do connect it to the internets.

The best method is to get a Xircom PE3-10BT ethernet adapter which will connect to the 1400's parallel port. The PE3 has a DOS ODI driver which will let you use a TCP stack like mTCP, WATTCP, PC/TCP, etc. mTCP includes a irc, ftp, telnet and other clients and works well.

Next would be to connect a Digi One SP or linux box running tcpser to the 1400's serial port and use it as a virtual modem. Either will emulate a modem connected to com1 letting you use a normal terminal software such as procomm, telix, qmpro on the 1400 to telnet.

Adam Ustine

Posted 2014-05-28T16:37:18.170

Reputation: 131

That sounds very interesting. the PE3 (early 90s) was not available with the tandy (late 80s) but it seems a realistic combination. If you got the PE3 running why would you add an additional "virtual modem"? – Clemens Bergmann – 2014-05-30T05:53:53.433

+1 for the internet connection that probably goes as fast as the main memory. I ran my Mac Classic online for a while, connected by SCSI (a parallel port bus) to ethernet. – Potatoswatter – 2014-05-30T09:54:18.587

Correct, no need to add a "virtual modem" if you were using the Xircom ethernet adapter. I only offered it up because running tcpser on Linux is virtually free vs $50-20 for the Xircom adapter. IMHO the serial port on the 1400 is too slow to be useful. Also the Xircom PE1 (PocketEthernet) was first released in 1988 just a year and some months after the 1400 so it's period correct for this device and does work well. – Adam Ustine – 2014-05-30T12:34:50.357

May I suggest that you try Minix v2.0? It will run on XT hardware like your laptop, although it will probably take some fiddling.

Minix 2.0 is reasonably full-featured and there is a contributed PPP driver that will also run on XT-style hardware. You can then use PPP over a serial connection to a properly networked Linux system. Finding an SSH client that will work on Minix with so little memory is more of a challenge, however...

thkala

Posted 2014-05-28T16:37:18.170

Reputation: 1 769

NAME: 1400 HD
MANUFACTURER: Tandy Radio Shack
TYPE: Portable
ORIGIN: U.S.A.
YEAR: 1987
END OF PRODUCTION: Unknown
BUILT IN LANGUAGE: MS-DOS, GW-BASIC & DESKmate delivered on disks
KEYBOARD: full stroke keyboard, 76 keys
CPU: NEC V20 (Intel 8088 equivalent)
SPEED: 4.77MHz or 7.16MHz
CO-PROCESSOR: Intel 8087-2 (8 MHz) math co-processor
RAM: 640 KB + 128 KB available for RAM-based disk driver or print spooler
ROM: 16 KB
TEXT MODES: 40 x 25, 80 x 25
GRAPHIC MODES: 640 x 200 (monochrome 9'' LCD backlight display), conform to IBM CGA
COLORS: 16 shades of blue with built-in LCD display. Colours with external monitor
SOUND: Sound beeper
SIZE / WEIGHT: 3.5 x 14.5 x 12.5 inches / 13.5 lbs 370 x 310 x 80 mm / 5Kg
I/O PORTS: AC adapter, Centronics/parallel (DB-25 F), RS232/serial port (DB-9 M), RGBI output for color monitor (DB-9 F), composite video output, enhanced keyboard (5 pin Din F), 2 internal slots (modem, I/O bus)
BUILT IN MEDIA:
LT & FD : 2 x 3.5'' floppy disk drives (DS DD, 720 KB each)
HD: one 3.5'' floppy disk drive (720 KB) + 20MB hard disk
OS: Tandy DOS 3
POWER SUPPLY: External PSU - 15v DC 700mA and internal battery (12 volt, 2200 mAh, 4 hours of continuous use)
PERIPHERALS: 1200 baud modem, 128 KB expansion RAMdrive, external hard-disk
PRICE: $1599 (USA, 1987)

According to the above specs, in order to connect this properly you would need to find the original 1200 baud modem listed in the PERIPHERALS section and connect using dial-up. 1200 baud = 1200 B/s. You will need something similar to the device shown on image below:

TRS-80 Modem DC-2212

eyoung100

Posted 2014-05-28T16:37:18.170

Reputation: 419

2The fact that weren't faster modems at that time, doesn't mean that the serial port itself can't do higher speeds like at least 38400 bps. – Cristian Ciupitu – 2014-05-28T20:08:48.810

@CristianCiupitu I'm not disputing that, but if the OP wants authenticity like me, he would stick with the modem. – eyoung100 – 2014-05-28T20:11:59.640

1I think that this might actually be the most promising Option. I would start with a "not that authentic"-variant with a newer modem and if I stumble upon an matching modem I would "downgrade" to that. Do you think that drivers might a problem? I have not worked with modems in ages. Do the just talk AT commands over RS232? – Clemens Bergmann – 2014-05-28T20:18:08.200

@ClemensBergmann, You're forgetting something here though. With the limit in RAM(640k + 128k add-in), your not authentic variant must be between 300 baud and the 1200 baud pictured, and must be external, unless the internal slots aren't used. Even internally, the speed can't be over 1200 baud. – eyoung100 – 2014-05-28T20:23:53.100

11200 baud and 1200 bits/sec are for all intents and purposes the same. So about 150 bytes/second, give or take. The four hours use time on battery is pretty impressive, though, all considered. – a CVn – 2014-05-28T21:15:16.143

@ECarterYoung that means I need a 1200 baud modem or can I use a faster modem in a slower mode? Also do you have experience with using modems in DOS? I am way to young (1985) to have used these in a decent manner. Do I understand it right that I would need a modem that has some kind of driver available for my old DOS or are these mostly interchangeable. – Clemens Bergmann – 2014-05-29T04:56:42.510

I don't believe you can slow down a faster modem these days. I could be wrong. – eyoung100 – 2014-05-29T13:48:16.830

Now, how would I connect that 1200 baud modem to the 1920 "candlestick" telephone on my desk? I think they would go together so well! :) (If I still worked in a cubicle, I'd love to put one of those phones on my desk just to confuse the iPhone-packing kids!) – Phil Perry – 2014-05-29T13:59:41.583

The model pictured above has no cradle. See this WikiPedia on Modems to see the answer to your question.

– eyoung100 – 2014-05-29T14:03:59.960

@ClemensBergmann a good terminal emulator knows how to talk to the hardware to do the necessary buffering so you can run much faster than 1200 baud. – Thorbjørn Ravn Andersen – 2014-05-29T14:40:16.320

According to http://www.8bit-micro.com/tandylap.htm the 1400LT has a built in modem

– James – 2014-05-29T20:44:55.757

@James The Listing was for an HD, not an LT. The OP needs to clarify – eyoung100 – 2014-05-29T20:58:06.063

The HD has one floppy and one hard drive, so it's not an HD. I reckon that is in fact a 1400LT and does have a modem, but it could be a 1400FD (which doesn't). More specs here.

– James – 2014-05-30T05:02:43.783

@vaxquis, It's fixed... – eyoung100 – 2014-05-30T13:59:45.420

Ok lets argue ove three hundreths of a byte... I added a tilde... are you still going to knitpick.... See http://www.physics.udel.edu/~watson/scen103/projects/96s/thosguys/baud.html

– eyoung100 – 2014-05-30T14:03:50.773

I won't argue oveR three hundreD byteS... Though I probably could still nitpick... ^_^ btw, what's with the link You provided? – None – 2014-05-30T14:10:29.177

Using that link allows you to convert baud to bits/sec – eyoung100 – 2014-05-30T16:45:05.480

You are not going to run Linux or any multitasking OS, the 8088 simply does not have the MMU required. Your only chance is DOS using something like Arachne DOS browser - or an old version of it that fits into your available memory. If only want to use it as a console, it's easy enough using a DOS terminal program.

Arachne

Posted 2014-05-28T16:37:18.170

Reputation: 51

2Multitasking does not require an MMU. – Potatoswatter – 2014-05-30T09:55:39.817

1Indeed, ELKS and Minix are examples of multitasking OSes which this machine can run. – Ruslan – 2014-05-31T13:59:44.487

Or Windows 3.x. I'm fairly certain Windows 3.0 could run just fine on an 8088/8086 (I know it ran on a 286, because I did at one point run it on a 286-equipped PS/2, and I think 3.1 could be made to run in standard mode on such hardware). It's multitasking, albeit cooperatively (not preemptively) multitasking. Not sure if you could cram even Windows 3.0 into 768 kB RAM, though, and even if you can fit Windows into that it won't have the RAM to do much of anything useful; 1.5-2.0 MB RAM is probably a practical minimum. But CPU-wise it should be okay, if you don't need a speed demon. – a CVn – 2014-06-02T09:57:04.790

One option that comes to mind, given that you admit in your question you only really want to use it as a SSH terminal anyway, would be to use a terminal emulator on the Tandy to act as a serial terminal to a more modern computer, connected over RS232.

You could still effectively "SSH out" to hosts on the internet although obviously in this case the laptop itself is not actually on the net. But it would definitely be a lot more usable.

Coxy

Posted 2014-05-28T16:37:18.170

Reputation: 1 586

Hi, that was also one of the first things that came to my mind. But I think for the sake of authenticity I think I want to at least leave the building without using a computer that is more powerful than the laptop. I have not used computers back then but what seems most authentic is placing a modem on a spare phone line connected to a spare server at work and use a modem at the Tandy to remotely dail in to the server. Do you think that this would be a realistic use case in the 1980s? – Clemens Bergmann – 2014-05-29T08:42:03.820

Oh yes, dialing directly into your workplace is a perfectly cromulent use case for those times. – Coxy – 2014-05-30T00:20:51.970

There is a DOS SSHv2 client around. – mirabilos – 2014-05-30T22:50:58.533

Try using a Console server / terminal servers / serial server / device server - different names for the same thing. You can connect to it via your RS-232 port (assuming you get the cable right - you may need to build one) and from there out via ethernet to the internet. But why bother. Its cheaper and more fun to get a Raspberry Pie, have a real linux distro on a modern processor, and if you want to go old school boot it up using the Risc OS or use one of the many available emulators.

Robert

Posted 2014-05-28T16:37:18.170

Reputation: 31

The modem connects to the motherboard with a 20 pin connector. Remove the internal modem. (It connects to the uart) U can use that connector and connect wifi to it. Then you can simply use a terminal program and some AT commands to connect to the internet wireless. There are many cheap boards that do this. There are bluetooth boards also. You can keep the com port to use for your mouse. Arachne is a very good graphical browser that runs on DOS. No need for linux, Dos 6.22 does it all.

Marc

Posted 2014-05-28T16:37:18.170

Reputation: 1

Unless you're doing this project as a hobby in and of itself, I would hesitate to even try connecting something that old and primitive to a network. It's likely to be far more work than you bargain for, and is very likely to cause system problems. If you're green and don't want to toss a working piece of equipment (I'm that way), a better use for this might be a direct serial connection (null modem?) to a headless server, as a maintenance console in a normally lights-out environment.

Phil Perry

Posted 2014-05-28T16:37:18.170

Reputation: 254

You should checkout what this guy has already done and not re-invent the wheel if you don't have it :)

http://users.telenet.be/mydotcom/library/network/dostcpip.htm

He describes how to get a TCP/IP stack working under DOS, although everything is using a dial up there are links to DOS browsers and other stuff.

silver

Posted 2014-05-28T16:37:18.170

Reputation: 101

Given that system specs you cannot run a current linux distro in that machine as said above but i think you can build your own linux to fit that laptop, check Linux From Scratch tutorials and maybe you can install a simple core linux with just a bash terminal.

2 other options are:

Become programmer (if you are not already) and build your own OS

Ask a programmer to develop an OS for you (look for arduino and small-medium devices programmers)

Isidro.rn

Posted 2014-05-28T16:37:18.170

Reputation: 1