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A podcast about home computers of the late 70's through the 80's. NEW SPONSORSHIPS! 8-Bit Classics is a great place to get video cables, power supplies and more for a wide variety of vintage computer platforms. Arcade Shopper has a wide variety of hard-to-find items for a large number of platforms.

Jul 28, 2015

The TRS-80 Model III and 4


On the personal computer timeline, we’re currently in the 1979 to 1980 time frame.  I do apologize that this month’s topic, the TRS-80 Model III and 4, is being presented slightly out of order in that there were a couple of machines introduced a little prior to this that I plan to cover.  However, as I already had this one recorded I decided to present it now rather than hold up publishing an episode just to maintain a precise order.


As usual, I have a short preamble before we get into this month’s topic, covering new acquisitions, upcoming shows, and a little bit of feedback.


I was lucky enough to get author and vintage computer collector Michael Nadeau to agree to co-host this episode with me, so this should be a fun and interesting episode.


Links Mentioned in the Show:



Interview with Co-Host - Michael Nadeau






Modern Upgrades




Current Web Sites


George Phillips
almost nine years ago

Really enjoyed the show, thanks for making it. I'm the fellow behind the Doctor Who video (not just audio) on the 4P. My name seems to accidentally be a secret. Extensive detail can be found here:

I've a few minor corrections. The Model III never came in an uppercase only version and the Model I supported 32 x 16 character mode; it wasn't introduced with the Model III. The Model 4 was introduced with all the cables (except cassette port and power) out the bottom like the Model III. I think even before the 4D they put the RS-232 connector out the back at some point. Except for the RS-232 the bottom cables weren't such a big deal since they're all card-edge connectors which naturally have a 90 degree connector.

I used the high speed cassette interface and while it sucked compared to a floppy it was otherwise excellent. Very reliable and the 3X speed over 500 baud made quite a difference. I think a large part of this was using a frequency modulation scheme rather than the square clock pulses of the 500 baud format. If we'd been able to afford a floppy we'd have dropped it in a heartbeat.

In case anyone gets the wrong impression, there was all manner of software available for the Model III including many games. The 128 x 48 graphics weren't great but nonetheless there were excellent versions of arcade games such as Asteroids, Targ, Berzerk, BattleZone and Defender. I've no direct original experience with the Model 4, but I do get the impression that few games were made that required a Model 4.

For support or generally connecting with other TRS-80 owners, I recommend this Vintage Computer forum: