Connecting a Tandy 102 to a Mac (Via Serial Port)

As the pace of technology marches onward, it becomes more and more difficult for computers of different eras to comminicate. Fortunately the RS-232 port has been around for a long time and serial communications based on it are likely to be in use well into the next century. Below are a list of requirements for connecting a Tandy 100/102 to a Macintosh that has a serial port (aka modem ports or printer ports). I would guess that with the proper USB-to-Serial port adapters that even iMacs and newer Apple computers can still get 'in touch' with a Model 102.

For my connections, I use the following setup:


  1. A Tandy 102
  2. A Macintosh with a serial port
  3. An ImageWriter I Cable

    This cable (Apple Service Part #590-0169) has a 25 pin 'D' shaped plug (DB-25) on one end and a serial 8 pin round (DIN) plug at the other. This is _not_ a Mac 'modem' cable. If you would like to make one for yourself, it has the following pin-outs:

    DIN 8



    6, 8, 20*








    4, 5*

    * Tied Together


On the Mac:

Freeterm, ZTerm, Red Ryder, or other text-based telecommunications program for the Macintosh.

On the Tandy:

The Model 102's built-in TERM program is good enough.


A) Setup the Cable:

1) The 25 pin end plugs into the RS232 port on the Tandy, and the 8 pin to either the Modem or Printer port on the Mac.

2) Launch the Terminal program on the Mac, and set it to use the correct port (Modem or Printer).

3) Launch the TERM program on the Tandy.

B) Set the Protocol:

4) On the Mac set the baud rate to 19,200, 8 data bits, No parity, 1 stop bit. Set the display to Full Duplex.

5) On the Tandy hit the 'STAT' command and type '98N1E'.

6) On the Tandy hit the 'TERM' command.

7) On the Tandy if the 'FULL' command appears, use it to switch to 'Full Duplex' communications.

C) Confirm the Link:

8) On the Mac type some characters. They should appear on the Tandy.

9) On the Tandy type some characters. They should appear on the Mac.

You can now upload and download text files using the 'DOWN' and 'UP' commands on the Tandy and the 'Capture Text'/'Upload text' command on the Mac. (Thanks Tom!)

More Info

Here are some more pages that explain file tranfers with the M102. (They will open in a new window.)

Return to the Introduction


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