atcomsystems.ca/forum Forums Other TDM Phone Systems 1A2 and Comkey Telephones & Systems A couple more basic questions

Hello all.

I found the fuses and the KSU is back up and running. I've wired the CO lines to the KSU and have three stations wired to test. Everything works as it should except none of the stations will ring. I've researched the board and, since this 551A doesn't have a ring generator, I gather making station(s) ring has something to do with the yellow/slate pair. Some questions:

1) Assuming the above is correct, where do I punch down the yellow/slate pair? To T/R where the stations connect or to the T/R where the CO line is coming into the KSU (or elsewhere)?

2) From what I've read, since there's no ring generator and the CO lines provide ring voltage, I may have only one station ring (per CO line) in that configuration. Why is that? After all, five or more SLT's will ring with only the CO ring voltage to work with. What concept am I missing?

3) If I cannot have more than one station ring per CO line, can I use the 10v buzzers (as used for the intercom) as an alternative? If that is a solution, what wiring is involved in making the phones buzz to signal an incoming call? Can a ringer be used on one station and buzzers on others?

If any of my assumptions don't seem quite right, I welcome your corrections and advise. Thanks for all the help so far.

Kind regards,

Mark

Mark,
1, I'll pass since I don't have a copy of the practice. Generally, the bells (or buzzers) are wired to the Y/S pair in the phone and connect to the "Common Audible" source, in the KSU or on a 66 block with provision for cross connecting to multiple Y/S pairs from phones.

2. The problem is that you cannot have more than 1 C.O. line connected directly to the same bell. If you only have 1 C.O. line in the system, then sure, all the phones can ring on it. But, if you have 2 (or more) lines and you connect them to the same bell (or bells), they will act as if they are conferenced together and tie up so that you will not be able to call out and callers will get a busy signal.

3. Yes you can use 10 or 18 volt buzzers for C.O. ringing. It just takes the correct wiring in the KSU, (again,see the practice) and buzzers rather than bells on the Y/S pair in each phone. In fact, most business 1A2 systems I installed were deployed that way.

Mark -

The Y/S pair is wired to the ringer in the set. You have a number of choices available to you.

1- You can wire the Y/S pair to T&R. It can be either T&R in or out, either will work.

2- You can buy a Ring Generator and add Ringing to the system and then wire the Y/S pair to the Common Bell output from the Line Cards and have each bell ring on more then one line.

3- You can use another voltage besides 90V Ringing Generator as a ringing source. For example you could use 10V or 18V AC or -24vDC, all of which are present in the power supply that you have. You would then have to use a different ringer then the one in the set. It could be low voltage buzzers (either AC or DC) or a low voltage bell or whatever else you like.

As John said, you could have more then one bell ring per line, but you can't have more then one line ring per bell - unless you use the Common Ringing circuit from the line cards and yes you can mix bells and buzzers and gongs and chimes and lamps and....whatever else you want.


Sam

Well, you actually can ring multiple lines to a single set of ringers if you are using 400D cards. You'll need to strap the options on each card for steady ringing. Then, you will need to strap the ring side of each line in as a back-feed to each CA lead for each line. Using the RG/RB output from the KSU (the last pair on the bottom-right side of the KSU's block) that is connected to the ringer(s), you'll be able to accomplish this.

This also assumes that you have a good ground to the KSU and you are using real CO lines, not fake VOIP or CATV ones.

Ed -

That's a pretty wild trick!

Sam

I have a standard Tellabs 8101 ringing generator (used) if you would like to go that route. They mounted better in a 584C panel though. You can PM me if you are interested.

I DO have a 118a RG laying around...if you still
need one.

Key system that will last forever. No software bugs there. Just someone wiring it wrong!'

ohhh my...you mean these things still have some value?? I just disposed of three or four of these...bummer...

DT98