Tandy TRS-80 Model 4

The Tandy TRS-80 Model 4 upgraded the all-in-one Z80 line with a 4 MHz processor, 80-column display, more memory and the advanced TRSDOS 6 environment. A compatibility mode continued to run much Model III software.

It was the mature desktop form of the original TRS-80 architecture and supported productive word-processing, education and small-business use.

Notable Features

• Zilog Z80A at 4 MHz with 64KB standard; expandable to 128KB.
• The principal display was Built-in 12-inch monochrome CRT; 80 x 24 or 64 x 16 text.
• Storage support consisted of Cassette on entry model; one or two built-in 5.25-inch floppy drives.

Historical Significance

• It was the mature desktop form of the original TRS-80 architecture and supported productive word-processing, education and small-business use.
• 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 4
Manufacturer	Tandy
Launched	Friday, April 1, 1983
Discontinued	1985
Launch Price	$1,999 with two drives
Country	United States
CPU	Zilog Z80A at 4 MHz
Units Sold
CPU Speed	4 MHz
RAM	64KB standard; expandable to 128KB
ROM	Model III compatibility ROM and boot firmware
Display	Built-in 12-inch monochrome CRT; 80 x 24 or 64 x 16 text
Graphics	128 x 48 block graphics; optional 640 x 240 high-resolution graphics
Sound	Programmable beeper
Storage	Cassette on entry model; one or two built-in 5.25-inch floppy drives
Keyboard	Integrated keyboard with numeric keypad and function keys
I/O	Printer, serial, cassette, expansion and external storage
Operating System	TRSDOS 6 / LS-DOS; Model III compatibility mode