atcomsystems.ca/forum Forums Other TDM Phone Systems 1A2 and Comkey Telephones & Systems 1A2 diagrams

I like the older equipment!

That did cross my mind. I can apply it to the 400E card: Pull the BR jumper, install TU and RG (Ringer Ground?) jumpers and the ringer relay is then tip to ground. Presumably you'd then just swap incoming tip/ring connecitons for ring-to-ground ringing.

I can't figure out anything like this on the San/Bar card though. I'm looking at the diagram from Carl's link:

https://www.kadiak.org/tel/4200a.jpg

As soon as you pull the BR link, the incoming tip side of the line doesn't seem to be going anywhere except the hold circuit via relay contacts K1A.

I think (it's been a long time)that the BR leads only strap the ringing to the CA (Common Audible).

Man, in late 1983 & early 1984 we were getting the brand new San~Bar "400" or was it "4000" cards delivered to us in the Air Force with Music On Hold (MOH) enabled by default. This was a major problem considering we did not use MOH at the base I was stationed at in those days. For some reason the cards put a hum on the line that was unbearable until we disabled the MOH feature.

The BR straps on the 400E diagram make sense, but according to the San/Bar diagram the BR strap just connects C.O. tip to station tip. As far as I can tell, if you pull the BR strap there's just no way you'd ever be able to use that line. :confused:

A couple of other points. First, I notice that all the cards have hold-release options of 50mS and 500mS, with the former being indicated as for use with ESS offices. Did all offices guarantee a minimum battery-drop period of 500mS upon calling-party hangup, or was ESS actually shorter? Obviously SxS/panel/X-bar might give momentary battery loss during relay switching which would necessitate the longer timeout, but as ESS (presumably) only dropped battery deliberately, was the 50mS a necessary setting on the line card, or simply a permissible setting but ESS still gave the full 500mS drop?

Second, and perhaps more simply, how often did customers specify the steady hold light rather than wink?

I do know that the "long" setting was intended for ESS offices. I don't remember ever having to change this setting whether the line was from an ESS or crossbar office.

The BR strap and B/R leads are two different things, but it appears that they both have been sufficiently described here.

Paul -

Before 1A2 there was 1A1 (Wire Spring Relay) and before 1A1 there was 1A (Flat Spring Relay). Under 1A (and I think 1A1 too) if you wanted wink hold it required another relay.

Additional relay = additional monthly charge.

Telco's charged extra for Wink hold and also (if I remember correctly) for Incoming Flash.

So, if you were upgrading a customer from relay to PCB and they weren't paying for wink/flash you needed a way to downgrade them.

Sam

Sam:

I know exactly what you are talking about. In New Jersey, I used to encounter those 1A1 setups all the time. That "system" was completely line-powered, so there really wasn't a way to power the lamps anyway. What made it even more fun was that it was field-constructed and those little metal housings for them were frequently placed in ceilings and nearly impossible to find!

They definitely charged an extra monthly fee for flashing lamps. I remember that well when I was renting equipment from NJ Bell at my home.

Ah, I see. The phone companies really liked to charge for every possible extra. I guess if customers moving to 1A2 were given wink-hold for free then existing 1A1 customers would have questioned why they were still paying extra.

I think locating 1A1 diagrams to study will have to be my next project.

Paul -

Someplace at home I have a Bell Systems book with drawings of 1A1 & 1A2. I'll see if I can dig any out and pdf them.

Sam

Many thanks Sam, that would be great!