8bit-Micro - TRS-80 Model III

TRS-80 Model III

WWW.8BIT-MICRO.COM ONLINE VINTAGE COMPUTER MAGAZINE

	DESKTOP PC'S Early Intel and Zilog CPU based portable personal computers. TRS-80 Model I TRS-80 Model III TRS-80 Model IV Color Computer Color Computer 2 Color Computer 3
	BUSINESS PC'S Early ultra-light personal computers based on Intel and Zilog CPU's. These units are all unique in their class. TRS-80 Model II Tandy Model 12 Tandy Model 16, 16b
	THE ODDITIES Once again systems caught between CPU developments. TRS-80, Tandy 2000 Tandy 1200 MC 10
	THE 1000 SERIES Simply the best personal computers built. Operated under MS-DOS 2.11 to 6.22. Based on the IBM PC. Jr. Tandy 1000, 1000a Tandy 1000SX ,1000TX Tandy 1000 SL,TL & TL2 Tandy 1000EX, 1000 HX Tandy 1000 RL, RLX

Introduced: July 1980
CPU: Zilog Z-80, 2.03 MHz

RAM: 48K
Ports: Tape (500 or 1500 bauds),

Parallel & RS232
Display: 12" B/W monitor built-in: 16

X 64 text
Storage: Two internal 178K floppy

drives, External hard drive

Operating System: TRS-DOS.

The TRS-80 Model III is essentially

the Model I integrated into one

complete unit, with all the upgrade

features that Tandy added to the

Model I in their subsequent release. It is probably Tandy most popular personal / business

computer in the TRS-80 line. Although designed for the business market, the Model III

has to it's credit an impressive collection of games.

The Model III has a 16 x 64 character display using a CRT very similar to the RCA picture

tube from a 12" television. The starting unit came with 16K RAM, and two single sided

5.25" floppy drives. Tandy built the computer with a daughter connector on the main

board to upgrade the unit for hi-resolution graphics. Edge card connections were provided

for external floppy drives, and parallel printer. The serial port was optional.

A few clones were built based on the Model III which were very successful in the business

market. Tandy provided a version of TRS-DOS, but the superior operating systems were

LS-DOS by Logical Systems or NEW-DOS 80. Clones were produced by LNW Corporation,

Sanyo, MTI Corporation and Adcock & Johnson to name a few.

The above images from left to right are: (a) Model III Clone from MTI, (Microcomputer

Technology Inc.) These units hit the business market and could be seen in may video

store operations. Bundled as a canned solution for video rental, the MTI held until the

late 1980's. (b) The LNW-80 with a color composite monitor. This unit was prevalently

based on the CP/M operating system. The original was introduced as a TRS-80 Model I

clone, the specifications were a 4Mhz., Z80A CPU, with Hi-Rez color graphics of 480 x

192, and could support full 80 column display this unit was complete with dual 5.25'

double sided floppies. (c) LNW-80 with it's green phosphor 80 column display without the

5.25" floppy modification.

Images from top to bottom - Left to Right: TRS-80 Model III, MTI Modified Model III, LNW-

80 w/ Drive Option and the base LNW-80.