atcomsystems.ca/forum Forums Other TDM Phone Systems 1A2 and Comkey Telephones & Systems Greetings and a Request for Some Info on How to Setup Small Keyset System

Cat 6 -

Originally the KSU was an empty box that held a slew of relays that were field installed and hand wired together by the Installer. Later iterations offered prewired relay packages (grouped by line). Still later, the relays were miniaturized and put on circuit boards. That's what you're going to see. All current KSUs have their origins with this equipment. It was the gold standard for Telephones for a generation (or three - depending how you count).

Sam

SilverSam,

From what I gather, the KSU doesn't sound all that different from a PBX, except that the PBX will contain all printed circuit boards instead of KTU cards. So the PBX is kind of the digital offspring of the KSU.

A bit simplistic, but not too far off the mark. That's a good way to make a comparison. The carcass itself doesn't do much but to provide slots and power to the cards. It is the cards and their connections that make things happen.

Cat 6 -

A KSU is a Key Service Unit. It services Key (multi button) Telephones, which usually pick up all, or many of the same telephone lines. There is no switching capability within a KSU.

A PBX is a switchboard (Private Branch eXchange). The original PBXs were cord (plug) boards where the switching was done by the operator. Later machines were PABXs (Private AUTOMATIC Branch eXchange) where the switching was automatic. Early models were mechanical, later they were electronic, recently they became digital.

In short a KSU allows many phones to access the same line or lines and share them. A PBX will bring both outside lines (trunks) and telephone extensions (sets) in and allow the connection between the two via a switching matrix.

I don't think I explained this terribly well. If I didn't, please advise me and I'll try to do better tomorrow, when I'm not so tired.

Sam

Sam, on point. Ed, egg-zac-lly.


Sam, if you did it any better you should be named Professor Sam.

Maybe we should promote him to GoldenSam.

That was a great explanation SS. Thanks! I know all about switches. In the world of networking we deal with them all the time.

Cat 6 -

You're welcome.

I teach a class on switching for the IBEW. It's a 3 part class - Voice, Data & VOIP.

Voice starts with mechanical switches (Stepper & Crossbar), goes to electronic and then to digital.

Data starts with Hubs and then goes to Bridges, Switches & Routers.

VOIP shows the convergence.

Sam

So she's up and running! I love the clicking sound coming from the KSU when a call is coming in! Plus the lamp flashing on the KSU is also a hoot!

Two problems though. I have a lot of noise on line 2, and line 2 does not ring when called, although lamp does wink.

I'll post pics once it's nice and pretty and all.

I'll try twisting the pairs more thoroughly. Maybe it'll get rid of some of the noise on line 2.