sundance-communications.com/forum Forums Other TDM Phone Systems 1A2 and Comkey Telephones & Systems KTUs and their Panels

I'm looking at two KTUs now on eBay and I'm hoping someone has some insight on either. These are:

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[*]WESTERN ELECTRIC PAGING AMPLIFIER 457C KTU. I have all 3 modular panels (620, 641A & 642A) and wanted to know if this works in any, and if so, wiring assignments. I could not locate any BSPs on this KTU. Any information on how this was used - never ran across it before, usually used PagePac addons.
[*]Western Electric/AT&T 455A KTU - Tone Ringing Signal. Same questions as above. I assume this was used in a Comkey 721 or larger system.

Thanks for any info! Jim

These KTUs were designed exclusively for use in ComKey 718, 1434 and 2152 systems. They were plug and play, meaning that there wasn't a BSP written to use them anywhere else.

The 620 panel won't help you at all, as it was designed for traditional line services in each slot via a 400 type line card. The 641 panels were for intercom cards exclusively. The 642 panels were for miscellaneous services. If my memory serves me correctly, the 642 panel gave you naked slots with traditional power assignments while giving you free access to all other card pins to do what you wanted to do. Check out BSP 518-215-419 for the details.

The 455A really only used -24VDC input and the warble tone came out (as referenced to ground) on what would have been the RN pin on a traditional 400-type line card. No other pins were used, so it was a fairly simple card to trick.

The 457C was similar. The audio paths took the place of what would be CO/Station tip and ring connections. Again, this card got its power via -24VDC.

Both cards were designed with notches in the card edge to prevent them from being plugged into a 620 type panel. This was to protect them from damage due to inputs of what shouldn't be there.

I will be honest and say that I managed to use a 455A as a tone ringing source when a customer with an existing 1A2 system asked me to add some of TIE's version of 1A2 sets to the system. It was ugly and required the use of relays so that I could keep traditional +/-105 VAC ringing present on the other stations. I did something similar when adding ComKey sets to another existing 1A2 system.

I had to send -24VDC in as the input in place of the ring generator that switched a relay. That relay then switched either ring voltage or tone ringing to the appropriate destination. Talk about a troubleshooting nightmare for a rookie!

Very cool, Ed!

Very cool indeed!

Sam

Those KTU'S were used in a 718/1434 Comkey systems.
You need Key System Service Manual Vol #3
Yes you can use them in the 642A Panel.

Thanks for the wealth of information. My very simplistic plan is to install the Tone Generator card in the 642A Panel as Phil suggested would work. Then find the tone output pair and treat it as a ringing generator output, and wire accordingly to the Interrupter inputs for a frequency generator. Then I'll connect the CA pair to the speaker located in each of my station sets (replacing the bell ringer). Think this will work? It's a hobby!

That's pretty much all that you need to do. The 455A only uses A (filtered) battery on pins 3 (ground) and 18 (-24 A battery). The ringing tone output is on pin 9 as referenced to ground. BSP 518-450-100 gives a good view of card schematics for the 7A (ComKey 718) system, which should be all that you need.

Every experienced 1A2 installer remembers that "pins 3 & 18" is the standard location of "A" Talk (filtered) battery input to a bunch of different types of 4" KTU's. For example, 401, 461, etc. Many KSU's come pre-wired with A battery & Ground. Sometimes, you need to disconnect those inputs, such as when installing a SanBar FM radio for MOH, which sends music on those pims, and line cards that receive MOH on those pins.

Keep in mind that just a speaker inside the set is not going to work. There needs to be some kind of amplifier, such as the one that goes inside ComKey 2832 sets. The output from the 455A is not very loud.

Ed, that is one important detail I overlooked! That's why there is a volume control wheel on the comkey sets. Need to rethink my idea since only the comkey sets come with amps, and I was planning on using a miniature speaker in 2565 and 2830 sets. Thanks- saved me a lot of unneeded work.