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?




Arthur P. Bloom
"30 years of faithful service...15 years on hold"