Round logo for The Computer Church -- a collection of rare computers and vintage documents that catalog the history of computing
The Computer Church
Home       Visit Us       Contact Us       About Us       Volunteers       Donate       Collection List      

 YEAR: 1975
 ITEM: Peripheral Device
 COMPANY: Southwest Technical Products Corp.
RARITY: Rare   Click here for further information on our rarity scale Information on the rarity of this item is unknown.

PR-40 Alphanumeric Printer


The PR-40 is a 5 by 7 dot matrix printer. That means it can print five dots across by 7 dots high...basically creating each character using different combinations of 35 possible dots (see example pictures). The printer could print a basic 64 character ASCII set, which includes 26 letters (upper case only), 10 numbers, and 28 special characters like punctuation or equals sign.

Instead of 8 1/2 x 11 inch paper that you might be used to, the PR-40 printed on a roll of paper that was a standard 3.875 inch wide and was commonly used by adding machines at the time and was readily available.

The printer was popular because it was compatible with many of the early computer systems of the 1970's including but not limited to the SWTPC 6800, the Altair 8800, and even the Apple 1.

In October of 1976, Steve Jobs wrote about connecting the Apple 1 computer to this printer. It was a good fit because the Apple 1 output to a video screen was exactly 40 characters...same as the PR-40.

Copyright © 2023 by Early Computers Project, All Rights Reserved.

Click on any of the images below to see the slideshow.
Front Top view Right side view Front close up Angled view Shown with brochure Example of 5x7 matrix letters Example of 5x7 matrix numbers