The SWTPC PR-40 Printer kit is a 5 X 7 dot matrix impact printer similar in operation to the well known Centronics printers. It prints the 64 character upper case ASCII set with 40 characters/line at a rate of 75 lines/minute on standard 3 7/8" wide rolls of adding machine paper. One complete line is printed at a time from an internal forty character line buffer memory. Printing takes place either on receipt of a carriage return or automatically whenever the line buffer memory is filled.
The printer can accept character data as fast as one character per micro-second or as slow as you wish to send it. The printer's seven parallel data lines are TTL compatible and may be enabled by a single "data ready" control line or by separate "data ready" and "data accepted" handshake control lines. This universal approach makes the printer compatible with all computer and terminal systems having an eight bit parallel interface; including of course the SWTPC 6800 computer and most "8080" based designs.
The printer mechanism is mounted on a black anodized aluminum chassis which houses the electronic circuits and the 115/230 Volt AC 50-60 Hz power supply for the unit. This makes the printer's overall dimensions 9 5/8" wide X 10 1/2" deep X 8 3/4" high.
Introduced by Southwest Technical Products Corporation in mid 1976 and the PR-40 kit cost $250.
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Black and White Photo (165k JPG)
Assembly Instructions (50k PDF)
Board Layout (133k JPG)
Schematic (390k 11x17 PDF)
Power Supply Layout (120k JPG)
Power Supply Schematic (100k PDF)
Wiring Diagram (440k 11x17 PDF)