The TRS-80 Model I, or just TRS-80 Microcomputer System as shown on the computer itself, was introduced in August 1977. It was one of the first low cost microcomputers available to the general public in large numbers, listing for $600 for a 4K machine. Given the fact that it was distributed through Radio Shack stores, its distribution network was already in place and quite large. The initial production run sold out in less than a month, and it took almost a year for Radio Shack to catch up with the demand. Radio Shack sold 100,000 TRS‑80 computers in 1978, over four times its nearest competitor. According to Tandy's website, more than 200,000 TRS-80 computers were sold from 1977 to 1981.

The machine initially came with 4K of RAM and included Level I BASIC and later was upgraded to 16K of RAM with the addition of a numeric keypad to the keyboard and Level II BASIC. There were four versions available; Level I with 4K RAM (26-1001), Level I with 16K RAM (26-1003), Level II with 4K RAM (26-1004), and Level II with 16K RAM (26-1006). Each came with a 12-inch video monitor, a battery/AC cassette recorder, a power supply and a two-game cassette.

The computer ran a Zilog Z80 at 1.77 MHz. The only means of storage was a cassette recorder. Unfortunately, its image soon started to be tarnished by problems caused by issues such as quirky connections between the computer and its external expansion chassis, quickly earning it the nickname 'Trash-80'. Despite these problems, the machine gained quite a following and was to be the first in a long line of computers sold through Radio Shack stores. It was followed by the TRS-80 Model II which was essentially the Model I and its display placed together in a single desktop enclosure.

The Expansion Interface, Tandy catalogue number 26-1140, -41, & -42, allowed the addition of up to 32K of RAM, up to 4 disk drives, serial and parallel devices.

The example in our collection is catalogue model number 26-1004, Model 1 with 12K ROM, 16K RAM and Level II Basic. Serial Number 008455

Other Systems Related To TRS-80 Microcomputer System Model I (26-1004):

Item	Manufacturer	Date
TRS-80 Microcomputer System Model I (26-1003)	Radio Shack - Tandy	1977
TRS-80 Microcomputer System Model II	Radio Shack	1979
TRS-80 Microcomputer System Model I (26-1104)	Radio Shack	1st January 1979
TRS-80 Microcomputer System Model III - David Jones's Machine	Radio Shack	July 1980
TRS-80 Microcomputer System Model III (26-1062)	Radio Shack	July 1980
TRS-80 Microcomputer System Model III (26-1066)	Radio Shack	July 1980
Tandy 102 Portable Computer	Tandy Radio Shack	1983
TRS-80 Colour Computer 2	Radio Shack Tandy	1983
TRS-80 MC-10 Micro Color Computer	Radio Shack	1983
TRS-80 Model 102 Portable Computer	Tandy Radio Shack	1983
TRS-80 Model 100 Portable Computer	Tandy Radio Shack	April 1983
Tandy 1000 Professional computer	Radio Shack	1984
Tandy Portable Wordprocessor WP-2	Radio Shack	1989
Tandy 1100FD Laptop Computer	Tandy Radio Shack	November 1989