TRS-80 Model I

TRS80 MODEL IThe TRS-80 Model I was launched in August 3, 1977 and is considered as one of the first computers mass marketed, fully assembled microcomputer. The microcomputer was created by Don French and Steve Leininger after 2 years working on the Model I along with 24 other team members.

The initial production run was sold in less than a month and it took almost a year for the company to catch up the 100,000 orders received during 1978. The Model I is composed in 3 pieces. The Monitor, The Computer itself which sits under the monitor, and the keyboard. An additional Tape Deck was also needed to operate the microcomputer. Later Tandy released a floppy Drive module and extended memory. The Model I it was later replaced in 1979 with the new Model II model.

TRS-80 Model I
Serial Removed
Zilog Z80 processor running at 1.77 MHz
4 kb (Basic Level 1) or 12kb (Basic Level 2) ROM. 4 kb / 16 kb depending on models (up to 48 kb) RAM 1 kb Video RAM
Mid Silver casing with Monitor, Computer and Keyboard separate. Full QWERTY keyboard with Black keys and white RETURN key.
Graphic Mode 128 x 48
Matrix with 2 colours monochrome. Displayable characters include the standard 96 text-characters with upper and lowercase alphabet, 64 graphics characters, and 160 special TRS-80 characters.
Simple Beeper driven by CPU.
1 x Bus expansion
1 x Cassette port.
Other modules could be fitted to expand the system such as RS 232C, printer ports, and External Disk Drives.
External Power Supply with Voltages of +12V & +5V
Dimensions 450mm x 530mm x 320mm (W x L x H) Weight Approx 25Kg including monitor.
Around 100,000 units Worldwide

The Club currently owns one TRS80 Model I complete with manuals and various other peripherals such as ram and Floppy Drive Interface. The machine is not boxed but aesthetically is clean and free from scratches.


Cassette Port

5 Pin Din 180
at the computer

Pin Name Dir Desc
1 REM IN Remote Control
2 GND N/A Ground
3 REM OUT Remote Control
4 AIN IN Audio In
5 AOUT OUT Audio Out