Technical Articles

Build your own Data Cassette Cable for your TRS-80


There is something very entertaining about loading and saving programs onto a simple cassette recorder.  One of the first commands you learn in basic are the CLOAD, for (cassette load) and CSAVE for (cassette save) syntax.  After all, if you don’t master these then writing programs in Level 1 or Level 2  Basic was mute.  That is unless your were rich enough to buy a disk drive.  In any case, when I pull out my TRS-80 Model I or CoCo waiting as the curser blink with abating breath is a real hoot.  That is of course as long as your volume on the cassette deck is not to high or the tape is not too noisy. 

It is also interesting to note, that in those days long ago, the interface cable that connected a simple cassette tape to your personal computer was for the most part built around some industry standards.  I found that Tandy / TRS-80, and many other brands, all used the same cable.   So if you are lucky enough to rummage at a garage sale or flea market you may still find one intact.  If one is not found, just build your own by following our lead.

Before we start, I want to make sure you all know that the ‘data recorder’ sold for your old vintage machines, like the TRS-80 CCR-81 and CCR-81 are just plain old mono shoe box tape recorders.  So start digging downstairs and find your Lloyds, Sears, JIL, Candle or Sanyo tape recorder for this project.  They will do just fine.  The only requirement is that they all have the proper ports on the side, which they all do.  It is very rare for them no to have the standard, EAR, AUX, REM and MIC ports. 

The standard data cassette interface cable consists of one 5-PIN DIN male plug (Radio Shack Part Number 274-003), one 2.5 mm male mono phono plug, and two 3.2 mm mono male phono plugs.

The DIN connector consist of 5 PINS apply numbered 1 through 5, and the mono phono plugs are simple two contact connectors, where the tip is the data contact the preceding barrel is the ground.  Wires are connected to these point using a soldering pencil and solder.  DO NOT try to accomplish this project using screw connectors, or wire wraps.  You run the risk of creating a short circuit, and the cable will not work.

You will also need either a number 20 to 22, 6 lead cable or three 18 to 22, 2 lead cables, preferably two to three feet long.  With your connectors, cables, solder and soldering pencil before you, you have all you need to build your own data cassette cable.

With your connectors, cables, solder and soldering pencil before you, you have all you need to build your own

Connecting the wires is a simple task of connecting to the right contact on the phono pugs while connecting the corresponding contact of the DIN plug.  The schematic above illustrates the proper wiring.

Give this project a try, and then pull out your old TRS-80, and Cassette Recorder, drop in a tape, and fire up Basic.  Then call over the neighbors and show them just how far you really have come.  They will me marveled!  As least you will have impressed us.  Good Luck and enjoy.