When Tandy introduced the TRS-80, the computer we know now as the "Model 1" or Model I" was simply called the TRS-80. No "Model" designation was necessary. The early releases were as follows:

  1. TRS-80, August 1977
  2. TRS-80 Model II, October 1979 (expensive model for business market)
  3. TRS-80 Model III, July 1980 (home computer successor to original TRS-80)
  4. TRS-80 Model 4, April 1983 (successor to the Model III)

One assumes the original computer was given and marketed with a distinguishing name once the Model II began to be marketed. Was it:

  1. TRS-80 Model I (Roman numeral to match the Model II)
  2. TRS-80 Model 1 (Arabic for simplicity, and make the Model II name seem "classy")
  3. Tandy never actually gave the original an official, distinguishing name.

I have searched, and have not been able to find an authoritative answer. Some sites use Arabic, some Roman numerals. If there was a distinguishing name given, would someone please post a picture of the box with that name, or perhaps an official Tandy advertisement using that name? (Without a picture, it didn't happen! 😉) A link would be useful as well.


3 Answers 3


I've gathered some pictures. Here is an early USA advert.

USA introductory ad for TRS-80

Note that it is never referred to as a "Model 1" or "Model I". It's just a "TRS-80".

Here is a later USA ad, after the Model II was released. USA TRS-80 ad after Model II released

Note that the price has gone down, but there is no indication that they have extended the name for the original model. The new Model II is specifically called out though. (The "Level I" refers to the low-end BASIC sold with the cheapest system.)

Here is a later ad from the UK. It also came after the Model II was released. enter image description here

Both the Model I and Model II names are specifically called out, in addition to the two Model I systems for Level I BASIC and Level II BASIC.

Tentatively these ads indicate that the original machine was publicly referred to as the "Model I" in the UK. The catalog Raffzahn mentions is for the USA (I looked it up), so at least in brochures, Tandy would refer to the "Model I" after the Model II came out. The middle image suggests Tandy did not feel it necessary to use the Model I designater in USA ads.


Radio Shack product names not infrequently differed from country to country, even if only subtly. This answer covers only U.S. naming.

But yes, the TRS-80 Model I was sold new under that name and always used the Roman numeral. This happened only after the Model II was released, and the full name including "Model I" was not used consistently.


1979 back page 1979 p.79

In their U.S. catalogs through 1979, before the introduction of the Model II, the Model I was always referred to only as the "TRS-80™ computer." See, for example, the back page and page 79 of the 1979 catalog, the latter headlined "The Breakthrough Radio Shack TRS-80™ Computer!"


1980 back page 1980 page 170 1980 page 174 1980 page 175

With the introduction of the Model II, Radio Shack starts using the term "Model I" sometimes, but not always, and usually only when a Model II is nearby.

The back page of the 1980 catalog has an inset headlined "New Low Price on Model I." However, at the computer section of the catalog starts on page 170 with the Model I but always called simply the "TRS-80™ Computer" or "TRS-80."

This continues through the next three pages until we get to printers on page 174, where the page is headlined "Add Printed Output to Your Model I or II TRS-80." Yet even there the product lines have things like "Cable for TRS-80 Expansion Interface" listed next to "Cable for TRS-80 Model II." (Arguably, that's fine because there was no Expansion Interface for the Model II, only the Model I.)

Even on page 175, where the catalog moves on to the Model II, the headline is "Meet the TRS-80's Big Brother!" though it eventually goes on to use "Model I" in the text, mostly:

...whose capabilities begin where the TRS-80 Model I approaches upper limits. Model II operates at twice Model I's speed, but it's not intended to replace — or compete with — the original TRS-80.


1981 back cover 1981 page 169 1981 page 170 1981 page 171

By 1981 the term "TRS-80" refers to Radio Shack's entire line of computers, not just the Model III but also the CoCo and the Pocket Computer (PoCo?), all of which were introduced that year. The back cover of the 1981 catalog has no reference at all to the Model I, but displays pictures and descriptions of the "TRS-80 Color Computer,", "TRS-80 Model III" and "TRS-80 Pocket Computer" under the headline "Radio Shack Introduces a Whole New World of Affordable TRS-80™ Computer Systems."

The computer section of the catalog starts on page 169 with a page devoted entirely to the Model I, but the headline "The Amazingly Expandable TRS-80™." Below this, however, the product description uses "TRS-80 Model I" (twice). Usage varies throughout the page.

The next page, page 170, introduces the successor to the Model I, headlined "The New Model III." The description compares it with "Model I," and "Model III" is used as a qualifier throughout on accessories such as disk drives that work only on the Model III.

Page 171 is headlined "TRS-80 Model I & III Software," and stating that "All programs will work on Model I or Model III unless otherwise noted." Just a few items have "Mod I only" beside them.

And the rest goes on in that vein.


1982 page 172

By 1982 the Model I itself is no longer in the catalog, though there is a small section of "TRS-80 Model I Accessories" on page 172. The software page still offers "The Growing Library of TRS-80 Model I & III Software," but "Mod I only" software is gone.


I did browse some of my racks and found that throughout all Tandy Computer Catalogues, starting with RCS-3 in 1979 (Page 6) the original TRS-80 was called TRS-80 Model I (Roman Numeral). Before that it was just called the TRS-80 (system) (RCS-1, 1977)

But in original Tandy manuals and documentations I did find many spellings as TRS-80 Model 1. So it seems as if they did keep the Model I seplling throughout all advertisement, but not over all.

Similar BTW for the early distinction between Level 1/2 and I/II BASIC.

  • I've been researching too. So far, it seems that in Britain the "Model I" designation was used. In the USA, though, I have found no evidence that "Model I" or "Model 1" was ever an official descriptor. Nor have I seen any images of the computer itself where the front plate or keyboard used anything other than "TRS-80". I've gathered some images, will post in a while. Would you and @wizzwizz4 like to meet in chat?
    – RichF
    Feb 23, 2018 at 22:08
  • From which country or countries were these catalogues? (Radio Shack often slightly changed product names from country to country.)
    – cjs
    Sep 18, 2019 at 15:00
  • 1
    @CurtJ.Sampson Mine are US issues. I got them from the US. A few back then, but most I bought way later when digging thru HAM flea markets in California :)) In fact, I don't have any German Tandy leaflets. Tandy had shops in Germany only for a very brief period in the early 80s, way before I started to collect materials.
    – Raffzahn
    Sep 18, 2019 at 18:51

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