TRS-80 Model III (Tandy/Radio Shack TRS-80 Model III)

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Hear John Freire talking about his Model III converted to a Model IV (12.6MB MP3) and about using an AM radio for sound effects for his TRS-80 (.8MB MP3).

John Freire came by the DigiBarn in December 2004 bringing this wonderful donation, a sterling TRS-80 Model III (3) which was converted into a Model IV (4) by Radio Shack for him. Indeed this is a very early Model III (number 133) but it has internals of the Model IV (more RAM etc) but retains the silver color of the III (the IV was white).

DSC01134.JPG	DSC01135.JPG	DSC01136.JPG
Note the serial port!	Note low serial number	DSC01139.JPG
DSC01140.JPG	DSC01141.JPG	Visitors Dec 3, 2004
"the Screamer" printer for the III	TRSDOS docs for the III	DSC01145.JPG
Popular game software for BBSs	DSC01147.JPG

Commentary by DigiBarn Curator Bruce Damer

I remember seeing this silver baby at our college when I started in computers in 1981 but it was only accessible to the system operators of our PDP-11/34 (I was jealous). It seemed to be a real computer with the built in keyboard and floppies. The DigiBarn's Model III is a relatively rare unit in that it does not have floppy drives. I was told that this was an option. I am not sure how useful this would make the unit but perhaps it was operating with built-in ROM BASIC.

From the TRS-80 Home Page's section on the Model 3:

The Model 3 was Tandy's second personal computer. One of the reasons it was developed was because the FCC instituted regulations about the RF emissions generated by computers (and other electronic devices). The Model 1 was completely unshielded (a fact many owners who also like TV and/or radio discovered the hard way), and was unable to pass the emission restrictions.

The Model 3 was somewhat better for new users because the monitor and keyboard were all in one unit. That got rid of the problems the Model 1 had with funky connections between the keyboard and expansion interface. The serial port was also usable. :-) The cassette interface supported both the 500 baud speed of the Model 1, as well as a much faster 1500 baud. Using a cassette based system was much less painful with the data screaming along at that speed.

The Model 3's BASIC ROM was 2k larger (at 14k) than the Model 1, added the 1500 baud cassette speed, allowed for left and right shift keys to be at separate addresses in the keyboard memory area, and added a 25 or 30 HZ real time clock routine (country dependent) which allowed for TIME$ to be added to ROM BASIC.

About the TRS-80 Model III (thanks Steadman Smith)

I know many people have contiunously bad-mouthed the TRS80 (me included), but this computer holds a place in my heart as it was the first computer I ever got real experience with and learned to program on.   My elementary school had a room full of these computers (about a dozen) and durring my time there I got to visit the computers about once a month to once a week on average. 

My impressions of these machines were that they were poorly designed to be used in a school.  ANY company that creates a big orange reset button on a grey bland keyboard is asking for trouble.  You try being a young child in school in front of a rather boring computer and NOT press the orange button out of boredom!

This computer did do one thing for me though, I learned the fundamentals of programing in a language called Snake.  Moral of the story?  No matter how crappy a computer might be it will inspire some people that don't have a computer of their own to learn more about them.  Even though I have chosen a differnet career than programing some of my fondest memories are of taking programing course later in high school and having fun with the network and the programs that I made that were exactly part of the course, and I would of never taken any of those classes unless I had met up with the TSR 'trash' 80 in my early school years.

See Also:

The DigiBarn's other Tandy/Radio Shack (TRS-80) computer systems

The TRS-80 Home Page's section on the Model III

8bit micro's pages on the Model III