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1980s Computers Explanation of terms

The SWTPC 6800

SWTP 6800


Southwestern Technical Products Corporation (US) (An established maker of quality hi-fi equipment.)

The 6800 was imported into the UK and sold by Computer Workshops of London.



Date Launched

July 1975


$395 as a kit,
$495 ready assembled.
These prices were for just the main unit. Keyboard, display, etc. were extra.
E.g. the minimum practical system comprising the 6800, a CT-64 keyboard/display terminal and a cassette unit for data storage cost $1024.90 in kit form.
In Britain, with 4 KB of RAM and a serial interface, the basic unit cost £275 as a kit or Computer Workshops would assemble it for an extra £75.

Microprocessor type

Motorola 6800 @ 0.98 MHz

ROM size

512 bytes containing simple operating system 'MikBug' (supplied by Motorola), including tape load/save routines.

Standard RAM

2 kilobytes

Maximum RAM

32 kilobytes using additional expansion boards and power supply.
Extra RAM cost $45 for 2 kilobytes.

Keyboard type

Various, typewriter style

Supplied language

A 3K, and later 8K, BASIC could be loaded from tape.

Text resolution

32 x 16 characters with TV display adaptor

Graphics resolution

96 x 64 pixels using optional GT-6144 graphics terminal card costing $98.50.

Colours available


Example Screenshot

6800 graphics adaptor screen
The USS Enterprise on the GT-6144 graphics display.



Cassette load speed

300 baud with optional AC-30 cassette interface at $79.50 (£65).

Dimensions (mm)
Weight (grams)

384 x 387 x 178
12000 approx

Special features

Up to 7 expansion cards could be plugged in.
Unlike many other early computers, the internal ROM of the 6800 meant it could be used as soon as it was switched on, rather than having to manually enter a bootstrap program via front-panel switches.

Good points

Could be expanded by the addition of serial and parallel interfaces, (low resolution) graphics, a low-cost ($250) dot matrix printer, even disk drives.
A fairly cheap system compared to other personal computers of the period.
A comprehensive level of documentation was supplied.

Bad points

The basic system was not really usable and several extra components (keyboard and interface, display adaptor, cassette adaptor) had to be added to make a full computer.

How successful?

Uncertain, but the range of accessories suggests it was at least moderately successful.
The 6800 remained popular in the UK for some time because it was cheaper than its rivals such as the Apple II and SWTP set up a factory in Peterborough to make ready-assembled units to order.


Southwestern Technical Products seem to have provided good support to owners of the 6800, with a full range of expansion options to turn it into a genuinely useful system, whereas some other manufacturers only seemed interested in selling a base unit.
Later the SWTPC 6809 model was released. This was similar to the 6800 but featured the more powerful Motorola 6809 microprocessor and cost $1500 including 48 kilobytes of RAM (a large amount for the 1970s.)

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