PR-40 Alphanumeric Printer
YEAR: 1975
ITEM: Peripheral Device
COMPANY: Southwest Technical Products Corp.
COUNTRY: USA
IN OUR COLLECTION: Yes
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.
Documents
Documents for this item have not yet been scanned or not yet posted. There are a lot of pages...contact us if you have an immediate need. (Although there are not a lot of "immediate needs" for a 70+ year old computer!)
Rare
This is a guess. The printer is rare but, so far, we have only tracked down about 20 of these printers.If you know the location of any other of these items, please let us know by contacting us at Director@TheComputerChurch.com .
OUR DEFINITIONS OF RARITY
One of a Kind: Only known existing item.
Exceedingly Rare: Only 2 to 10 known to exist.
Very Rare: Only 11 to 25 are known to exist.
Rare: Only 26 to 50 are known to exist.
Difficult: Difficult to find.
Available:Can be commonly be purchased.
Unknown: We cannot make a determination.
(For comparison: Many people consider the Apple-1 computer to be rare. As of 2025 there are 92 confirmed and probable Apple-1 computers.)
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