Tandy TRS-80 Model III

The Tandy TRS-80 Model III integrated the computer, monitor and optional floppy drives into one cabinet while improving radio-frequency shielding and reliability. It replaced the original Model I as Radio Shack’s mainstream Z80 computer.

Strong Model I software compatibility and a cleaner all-in-one design made the Model III widely used in homes, schools and small businesses.

Notable Features

• Zilog Z80A at 2.02752 MHz with 16KB or 48KB; some cassette models sold with less.
• The principal display was Built-in 12-inch monochrome CRT; 64 x 16 text.
• Storage support consisted of Cassette and up to two built-in 5.25-inch floppy drives.

Historical Significance

• Strong Model I software compatibility and a cleaner all-in-one design made the Model III widely used in homes, schools and small businesses.
• Radio Shack’s large retail network made demonstration, sales and support available well beyond specialist computer dealers.

Collector’s Notes

• Factory memory, drive configuration and regional badge should be checked because many surviving systems were upgraded.
• Original monitors, manuals, software, storage hardware and Radio Shack peripherals add historical context.

Specifications

Technical Information
Name	Tandy TRS-80 Model III
Manufacturer	Tandy
Launched	Tuesday, July 1, 1980
Discontinued	1983
Launch Price	$699 cassette model
Country	United States
CPU	Zilog Z80A at 2.02752 MHz
Units Sold
CPU Speed	2.02752 MHz
RAM	16KB or 48KB; some cassette models sold with less
ROM	14KB Level II BASIC and system ROM
Display	Built-in 12-inch monochrome CRT; 64 x 16 text
Graphics	128 x 48 block graphics; optional high-resolution boards
Sound	One-bit sound through cassette output
Storage	Cassette and up to two built-in 5.25-inch floppy drives
Keyboard	Integrated typewriter keyboard with numeric keypad
I/O	Cassette, printer, expansion, optional serial and external storage
Operating System	Level II BASIC and TRSDOS 1.3