Seriss Corporation - 1A2 Key Phone System Equipment



1A2 "Single Board" KSU
These boards are an easy "single circuit board" solution to managing multiline "1A2" business phones popular in the 1950's - 1980's in the United States and other countries, collectively called "key systems".

The current version of this board is REV-J6A.

Board revisions are, in progression of new-to-old:
J6A, J5A, J5, J4, J3, J2, J1, H / H1, G1, G, F1, F, E, B.

You can see the entire revision history which describes in great detail what's different in each board revision.

If you're interested in these boards, contact erco@seriss.com with the email Subject: "1A2 KSU Inquiry" and I can supply ordering info for fully assembled/tested boards. Try to include info on which phone models you expect to use with the board, and any other details/questions you can think of.

Amphenol ⇌ RJ45 Cable Reducer & Expander
These boards let you use simple RJ45 cat5/cat5e network cabling to interconnect 1A2 phones to the Seriss KSU without needing 25 pair cables or 66 blocks.

Lines 1,2,3 and 5 as well as bells and buzzers can be carried over three RJ45 cables without any special punch blocks or configuration. Fewer cables can be used for fewer lines. (Line 4 is not supported; to fully support 5 lines or more, you should use 25 pair cable.)

Designed mainly for use between 1A2 phones and the Seriss KSU, but can also be used with other KSU's such as Western Electric 551a/b/c and 620 panel KSU's.

Click here for details.