No Audio in Cisco IP Phone 7942

[aadewole1]

I have a Freeswitch installation with various models of Cisco IP phones whose firmwares have been upgraded to use SIP, all models work fine except the 7942 model. When call is placed through to the 7942 series from other models, there will be no audio in both directions. However, if the 7942 initiates call to any other model the audio is fine in both directions. The network is not behind NAT and other devices work fine on the network, what could be the problem?

[Manish Gogna]

That's pretty weird. What happens if one 7942 calls another 7942 and have you tried swapping the switchport of one of the 7942 with some other model of op phone to see if the issue follows the phone or switchport. Check if the up phone firmware is latest one.

Manish

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[aadewole1]

Really weird, if one 7942 phone calls another 7942, there is no audio in both directions, yes I have tried swapping the switchport, if 7942 calls another model for example 7821, there is audio in both directions but when another model calls 7942 there is no audio in both directions, its really driving me nut

[Manish Gogna]

Do you see and Tx / Rx packets if you press "?" on the IP phone while there is no audio. Can you get detailed callmanager trace and pcap for a test call to see if the signaling part is okay.

Manish

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[aadewole1]

The image attached is the flow Sequence of the communication between 7942 and 7821 when call was initiated by 7821, it shows no RTP port negotiation between the two devices

[Manish Gogna]

Hi,

Can you share the detailed callmanager trace for a call with this issue, also share the phone firmware and cucm version.

Manish

[aadewole1]

As I said earlier I am using Freeswitch and not Cisco CallManager, attached is the SIP trace from Freeswitch and the cucm version for the phone is cmterm-7942_7962-sip.9-4-2SR1-1. Thanks

[aadewole1]

But when 7942 initiates a call, everything works fine, port negotiation was successful and audio is good, see the attached image

[Achubet14]

Was there ever a solution to this? I work at a midsized company with multiple locations. Each location has cisco phones (mainly 7942 but some 8845). Only certain phones at one location cannot hear, or be heard, to only one other location. This is not a site-to-site issue, because it is only 2 phones. We replaced the 2 phones and the issue is still present. Does anyone have any ideas?