atcomsystems.ca/forum Forums Telephony Discussion Phone & VoIP Systems Panasonic Telephones & Systems Problem with CO lines not releasing

Installed a TDA100 with a TVA50 back in 2009. Just started having problems on CO lines 1 and 2 were the buttons on the phones are lit red as if someone is using the line but nobody is. Its like the line is stuck and wont clear so you can use it. Very random too. Only has happened 4 times in the last 3 weeks. I went around and unplugged each phone and plugged it back in to see if it was a bad phone but the light stayed red through that whole process. The only way I could clear the light is to shut down the system and turn it back on.
They are using an LCOT16 card.
Any ideas on why a line gets stuck like that and happening very random and not all the time??
Thanks

No disconnect signal from CO?
If you have spare ports move lines and reprogram buttons.

Remove the CO line from the system. Did the light go out when you removed the line? Could be CO line trouble. Could be CO disconnect as stated above.

Has the customer changed their local exchange carrier recently?

YES = you have isolated the problem. You can check the archives for thousands of words that have been written about this problem that has been caused by CLEC's not playing by the rules that real telephones companies play by.


NO = read on, below.

You say "CO lines 1 & 2" Can we assume that those are the only lines on the system? Are there others? Do they work OK?

Unplugging things at random, especially tel sets that have nothing to do with how the CO lines are handled, will not tell you anything.

Try to re-create the problem. Use your cell phone and call one of the affected lines. Establish a conversation with one of the extension phones. Put the extension on HOLD. Put an analog voltmeter across the T & R of the CO line and watch for the CPC open when you hang up your cell phone.

If you do not see the open, AND the extension stays on HOLD, then the carrier is not sending the required CPC.

Continue to watch the HELD extension, and physically remove the bridging clips for the trunk in use. Does the HOLD light go out?

And, of course, the obvious. AA/VM has been penetrated and is being used for nefarious purposes. unauthorized CF to long distance services. Check the phone bill.

L. Horse, of course, I should have thought of that. Sometimes you have to think like a criminal, and I forgot that possibility.

Using a butt set on the HELD line would reveal any conversation that's in progress, but not expected.

This is a case of needing to do a lot of tests before asking people who are not at the site to help. It comes with experience. Once you've solved this problem, the next time it won't be such a problem again.

Good luck, and keep us posted with what you find. (Fingers crossed)