Phone Can't Hear External Call Audio

[derekvw91]

I've got an issue that's a little perplexing.

We have a DID assigned to call group. Two phones are in the call group. One is a Cisco 508G and the other is a Panasonic cordless phone. If the call is answered on the cisco phone, the phone can't' hear the caller's voice. If the call is answered on the cordless phone, everything works as it should. If I call the cisco phone internally, the phone works just fine. If the Cisco phone makes a call, everything works as it should.The issue only seems to happen on inbound calls and only on this one phone. Any other calls to any other DIDs, Call Groups, etc all work fine across the system.

Things I've done to try and remedy the issue:
1) Reset the phone and reprovision
2) Swap out the phone with another 508G
3) Change ports on the switch

Any suggestions?

 

[lneblett]

How was the Cisco provisioned and was it factory reset beforehand?

Take a look at the codecs in use by the phone and the provider. You may also want to try and turn on "PBX provides audio" on the Cisco extension. Also look at re-invite and replaces header and try these options on the Cisco extension.

 

[derekvw91]

The phone had been previously working before. We had a power outage that made the switch in this building lose it's configuration data. I reconfigured it and two of the SPA508Gs started working fine, but the other did not and exhibited the issues I described above. We're also using multiple 508Gs across various buildings without an issue.

The 508G was provisioned with it's firmware updated, then factory reset, then provisioned. When it started to exhibit issues, I reset it and reprovisioned. We have DHCP 66 enabled so the phone automatically picks up it's provisioning.

As we have multiple other 508Gs working, I don't see why I would need to configure this one device differently, but I'll take a look at enabling those features on this extension.

 

[leejor]

Are the sets on the same LAN as the 3CX server? If remote, then check the sets local port number to see if there is a conflict, if not using the SBC.

 

[derekvw91]

Both phones are in the same local subnet as the server.

I tried enabling PBX delivers audio. The issue still persists.

Could it be that the extension/phone group could have been corrupted?

 

[leejor]

Did you check the 3CX Server log for any signs of error messages just after a "failure"?

 

[derekvw91]

No warning or error messages are listed in the logs after a failure.

The receptionist did tell me today that the issue is now intermittent. Some calls work fine, other calls still have the issue. This is only happening on this one extension.

 

[leejor]

This is only happening on this one extension.

Have you tried replacing the set? Perhaps this is a hardware issue, loose handset cord, sort of thing.

 

[derekvw91]

Well now I just got a call saying that it's happening on both phones. It seems isolated to just one DID though.

 

[leejor]

Hmmmm... well since the common denominator now appears to be the DID number and not a particular set, you need to look at "how is that number handled differently". I'm assuming that all other DIDs from the same provider are working with no issues. Did you try removing the extensions, from the PBX, along with the DID programming, then re-provision?

Have you made any changes to your network about the time this began? Did this problem just "come out of the blue" or has it been this way since the "problem" DID was installed? are all extensions running through the same switch? have you tried moving the extensions with the issue, to another switch? A unlikely as it may be, it could be a network hardware issue.