Hello Everyone,

I am very excited to start my Western Electric 1A2 551B KSU project and I have some questions about the 551B KSU. The information that I was able to research, that the KSU was not designed/built for dial selective dial intercom.

Since I only would need 3 lines, can the 4th card slot be used for manual intercom? If so, would I have to do any type of rewiring on the punch down block?

Would you guys recommend the manual intercom card 401A or the 401B card?
Also would any of you have a manual intercom card for sell or would you know a good place to get one? No luck on Ebay…..

Can I add a dial selective dial intercom like Telton or Valcom and use a external punch down block down the road?

Since I will be using manual intercom, how would you wire up the manual buzzer buttons (the small black box with a little white button that attaches to the phone) I think those are (551A SIGNAL KEY) to make the buzzers work from the phone to the KSU. I could not locate any info about that in the Bell System Practices.

Since the KSU does not have a 118A frequency generator ringer and I don’t know if my VOIP lines will have enough ringing voltage to make the phones ring, could you use the buzzers in place of ringers? If so how would you wire the phone or the KSU?

What line cards would you guys recommend to use in this KSU? My ITT 511 KSU seems to like the ITT 400 E cards..

If you guys could let me know a good place or if you want to sell some line cards, a intercom card and some amphenol cables.

Thanks



[Linked Image]