Basic phone on a 1224EX rings and answers but no voice path or CO dial tone on two ports

[jasto1137]

2 Basic phones were added to a 1224EX system that had 8 phones already on it, *08 set to Basic, *01 set to class of service 1, *05 set as CO 01 to 03 on flex buttons, *13 and *14 all 10 phones set to ring day or night, phones are on ports 3 and 4 and set to station 12 and 13, just hear DC, no CO dial tone, on CO line 1,2,or3 selection. Incoming CO ring and light, answer of incoming CO call stops the ring but no voice. Port 4 used to work OK when 8 phones in use. Is there an 8 phone limit?

 

[mforrence]

I THOUGHT those KSUs were flat-packs, but it could easily be that it's a 308. Have you tried a known working phone on the ports and/or tried your new phones on a port with known working phone? If you have a 4th line, it would indicate that you're built as 616. Maybe look under the hood? That is certainly a "classic" phone system - new in the late 80s or early 90s.

 

[jasto1137]

The phones all work in other positions when swapped. It is a GK-1224EX according to its name plate, and it is wired for phones 10 to 20 on the Bix blocks from the amphenol plug in connector. The second bank is not wired, and I have been unable to swap intercom numbers above 21, so it probably lacks an expansion card for stations 13 to 24. I've been avoiding a full restore to default as it will probably erase all the speed dials programmed on the various phones in use. And yes it is a classic, but surprisingly had many features in spite of its age. Its a Zilog Z80 processor system, a real old timer. I have one port unused which I will try to see if it works and report back. Thanks for the reply.

 

[mforrence]

If you've opened cabinet to see processor, you can also see if it has expansion cards. There MAY have been a version where you had to specify what type of keyset was plugged in - but I doubt on that era.

 

[jasto1137]

Well, the answer to this dilemma is ridiculously simple, the supplied phone to wall 4 conductor cables were wired pin 1 to 1, pin 2 to 2 etc. They are supposed to be reversed so pin 1 goes to pin 4, 2 to pin 3 etc. Since they were not reversed, the inner pair which is the voice pair was reversed. When this happens, the phone gives you side tone, but no connection to the trunk (outside CO) lines when you push the CO line buttons. The data pair does not care if it is reversed and continues to light the lights, and you can press an incoming CO line to answer it but no voice connection occurs. So there you have it. I interchanged the new cables in troubleshooting, but they were both improperly wired. Cost me a fortune in time to pull the wiring for these two phones apart and trace all over the building. Hope this helps someone else running into problems with this type of system.