1a2-pic
This is the PIC chip firmware for a 1A2 Multiline Phone Control Board,
which controls old AT&T 1A2 business phone systems which were THE phones
used in business from the 1950's on through the early 1980's.
Revision "G" firmware is being used on all boards REV G and after.
I've been using the release tag "v1.3c" for all release boards so far.
(Although v1.5 is newer, v1.3c is what I've standardized on)
Some people still like using these rugged multiline phones which can
be integrated with modern technology; IP telephones, Cellphones (via
Bluetooth gateway devices), etc.
The project uses a PIC16F1709 to manage hardware logic on the PCB, in place of
analog/discrete components used in earlier versions of the printed circuit board
(revisions A through C).
The temporary R&D the page for this project is currently here:
http://seriss.com/people/erco/tmp/pic/
..which shows the current status of the PCBs, schematics, documentation,
user manual, circuit description, etc.
This circuit board handles doing what AT&T's original KSU boxes (Key
System Unit) do, but as a single PCB board simple solution. The original
AT&T boxes were large and heavy and somewhat complicated to install.
The smallest of AT&T's boxes were steel, about the size of a large shoe
box, and had several PCB boards in a rack, along with a punch block,
heavy power supplies, motor powered rotary switches, etc.