UCM6204 Outgoing Calls not working on Analog, connects on receiving end but just ringback tones endlessly at origination point


I’ve been trying to get an answer for this one for months from GS support with no luck. I don’t think they understand the problem or maybe I’m having difficulty explaining it.

I’ve got 3 analog lines on FXO ports 1, 2, and 3 (Charter Spectrum Business) connected on my UCM6204, latest firmware. I can receive calls no problem on the analog lines. But when I make an outgoing call on the analog trunk, I get ring-back tones, the receiving phone rings and can answer the call, but the ringback tones continue on the phone the call originated from. It just rings forever until it times out. No audio on the call on the receiving end. I can make SIP calls out no problem, just the analog giving me trouble. I’ve been going at this for months and tried every conceivable combination of settings, no luck. Also couldn’t find a similar issue mentioned anywhere in the forum or elsewhere.

Any help would be appreciated.


This is pure PSTN or converted from ISDN ?


Not really pure PSTN. They come out of the modem…from the cable line. Only thing available at this location.


Modem ? It is ISDN then probably with converter.
Try check if Provider set this box with your country regulation. I seen many times that it was not set property and gateways have problem with such settings.
If you have 2 lines then do TEST on PSTN and see results.


Who made the connection from the modem to the PBX? What make of modem. Who is provider?