Atari Portfolio Serial Interface: How To Get Terminal Software

I’ve had an Atari Portfolio HPC-004 for a couple of years now. It’s a slick little palm-top: solid state memory, MS-DOS compatible, 4 AA batteries as power source. It also has a docking slot on the right side for extra peripherals. This enables you to add communications ports that are otherwise lacking like a parallel or serial port. I’ve been seeking a second hand serial interface (HPC-102) for some time but have come up empty. I decided to instead purchase one new.

Atari Portfolio and Serial Interface

Atari Portfolio and Serial Interface

Yes, Brad at Best Electronics still has a stock of new and reconditioned Atari Portfolios and peripherals, including a brand new Serial Interface for $59.95. The only caveat is the manual is in German only. No big deal considering it doesn’t really need a manual.

The Serial Interface is about 1/3 the size of the Portfolio and gives you a standard 9-pin RS-232C serial port capable of 110 to 9600 baud. You can change the parameters of the serial port by accessing the Portfolio’s setup menu with Atari-S. From there, choose RS-232 port and which reveals settings for baud rate, parity, and data and stop bits.

Atari Portfolio Serial Interface and Manual

Atari Portfolio Serial Interface and Manual

This is great, but now you need a communications or terminal program to actually do anything useful like transfer files or dial a BBS. I did a quick search and it seems that the easiest method to transfer files is to use the built in file transfer utilities with the Parallel Interface.

Your use may require additional hardware/software.

Your use may require additional hardware/software.

Unfortunately, I don’t have one so I kept searching. Another link listed a method to hand-type in binary code which resulted in a small program to transfer a file using the serial port. The method looked like it was easy to make mistakes, so I passed.

Another link detailed the method I was looking for. This method used the DOS copy command to save data from COM1 that was transmitted from a PC with a serial port. I don’t actually have a PC with a serial port anymore, so I had to use Virtual Box on a Mac with a USB to serial adapter. The instructions called for setting the baud rate initially to 110 for the DOS copy command. My guess is this is likely due to keep the speed as low as possible since there’s no error checking.

USB to serial null modem cable

USB to serial null modem cable

I connected the Portfolio with a USB to serial null modem cable and proceeded to give it a try. I setup everything and ran STARTX.BAT. This is where I had problems– it kept failing. I tried several different USB to serial adapters, different cables, confirmed wiring. All ended with “Not ready error, Abort, Retry, Ignore?” on the Portfolio and an empty file. I began to wonder if existing USB to serial adapters can even do 110 baud any more. I wasn’t able to find any conclusive evidence they didn’t support 110 baud, nor any that confirmed they did. All spec sheets listed 300 as the lowest.

I should able to use any baud rate I’d like, as long as I slow the per-character flow over the link. I remembered that CoolTerm has a setting that lets you add a transmit delay for each character. I abandoned the Virtual Windows instance and went to CoolTerm. Here are my steps.

How to transfer xterm to an Atari Portfolio with a Mac or PC

  1. Connect the Mac/PC and Portfolio together with the USB to serial null modem cable.
  2. Download and Unzip both. (On my Mac, I had to use the command line unzip tool in Terminal.)
  3. Set CoolTerm on the Mac/PC and the Portfolio to 300 baud, 8N1 and no flow control.
  4. Set CoolTerm to have a transmit delay of 10ms.
  5. Type “copy com1” on the Portfolio (don’t hit enter yet).
  6. Choose “Send Textfile” in CoolTerm and select the “” file (don’t hit OK yet).
  7. Hit enter on the Portfolio and then hit OK on CoolTerm.
  8. The file should be sent and you should see “1 file(s) copied.”
  9. Change the baud rate to 1200 baud on both CoolTerm and the Portfolio.
  10. Remove the transmit delay in CoolTerm.
  11. Type “” on the Portfolio (don’t hit enter yet).
  12. Choose “Send Textfile” in CoolTerm and select the “” file (don’t hit OK yet).
  13. Hit enter on the Portfolio and then hit OK on CoolTerm.
Atari Portfolio with xterm

Atari Portfolio with xterm

If everything worked, you should be rewarded with a terminal program on the Portfolio. Type “xterm” to launch it. Change baud rates using the same system setup menu (Atari-S). Receive a file with XModem with F2.

If you received a single character response from xload, you can look up the error code by reading the “startx.bat” file.

Atari Portfolio and WiFi Modem

Atari Portfolio and WiFi Modem

Now you’re ready to hit the boards and relive the hay-day of computing before the Internet. Use tcpser to setup a virtual modem with your Mac, PC or even a Raspberry Pi. Or if you’re lucky enough to have a WiFi modem, you can use those too. For a list of online BBSs, visit the Telnet BBS Guide.

Let me know if you’re able to get it working in the comments.


6 thoughts on “Atari Portfolio Serial Interface: How To Get Terminal Software

  1. Permalink  ⋅ Reply

    Pete Fletcher

    April 15, 2017 at 4:34pm

    Your inspiring me to get a Portfolio again. Great post!

  2. Permalink  ⋅ Reply


    May 23, 2017 at 12:11pm


    you Tutorial was the first one that was working for me. Tanks

  3. Permalink  ⋅ Reply

    Kevin Warnalis

    October 23, 2017 at 8:10pm

    duly noted the link to the first site I provided you with actually has a correction to the serial port owners manual so please bear that in mind

  4. Permalink  ⋅ Reply

    R. N.

    December 4, 2017 at 12:31pm

    Hey i own two Atari Portfolio for some years and i wasn’t able before to transfer acom over serial some years ago from that DOS method… Ended up grabbing a parallel interface already a good while ago but never got around digging up an old parallel cable or buying a new one haha. Anyway.

    Thanks a lot for your tutorial, I didn’t know of CoolTerm for Mac — I had no idea about that 300/110baud thing — i was able to get xload and xterm2 on my Portfolio 256k card. Although i can’t get to transfer any other Portfolio file with xterm2 it seems :/ Guess i’m not used to these old protocols… But i could send data I’m typing to the Portfolio from a Raspberry Pi on Linux using Screen over USB/Serial – and with xterm and CoolTerm with echo i can see the data typed too…

    Any idea? How do you do it? I must be doing something wrong obviously.

    (Also just in case you might have an idea… Both my Portfolio have a bug/problem. One has a missing LCD “pixel” line. The other one when in the “OFF” state i can see the screen flashing black every X seconds. Which will drain the battery. I read something about it yesterday googling quickly about tons of stuff but… Just in case. I don’t know if both Portfolio have the same BIOS version, i don’t think, i need to see that again. Not sure about the Rom updates either. One is a HPC-004 and the other a HPC-006.)

    Thanks 🙂

  5. Permalink  ⋅ Reply

    R. N.

    December 4, 2017 at 8:30pm

    Ok well, nevermind my previous post i guess. I managed to use xterm2 to receive files with screen & lrzsz by xmodem on Mac. No idea why screen wouldn’t work correctly later on my RPi 3 but that’s probably because of my old Ubuntu Mate SD. (I’ll try with a Raspbian on a Pi Zero later…)

Leave a Reply to Pete Fletcher Cancel reply

Your email will not be published. Name and Email fields are required.