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C40 audio problems

Lester Wilson


I have a C40 running TC5.1.8.303428.

Problem I'm encountering is I'm hearing no audio - either ringtone when someone is calling the C40 or audio from any conference participant. 

Call status shows for both transmit and receive:

Protocol:  AACLD - Mono

Channel Rate:  63 kbps

Total Packet Loss:  0.0%

Current Packet Loss:  0.0%

Jitter:  0 ms

I'm not having any trouble with pass-through audio from the PC (PC speaker out to C40 line in to C40 line out to loudspeakers). 

Was originally running TC5.1.5.297625 and then upgraded it to TC5.1.8.303428.                    

Rebooted the system.  Factory reset the system.  No luck. 

Have an open case with Cisco TAC - but awaiting support entitlement (the customer purchased SmartNet on these devices through us, but the paperwork is still in process). 

Until then, any help would be appreciated.  Thanks!

3 Replies 3

Bhaskar Jha
Cisco Employee
Cisco Employee


Are you able to play ringtone locally ? Navigate to menu with remote and do the same.

Are you using HDMI for audio or line out with external speakers ?

Are there anything else connected ?

Is it direct speaker to codec ?



Actually I'm all set now.  Speakers are part of a SMART Board setup.  Being unfamiliar with those devices - PC audio was being routed to the speakers via USB and I was not aware of that until further troubleshooting.  For some reason the audio inputs on the bottom of the SMART Board were not functioning correctly and I just bypassed that - went directly to the speakers on the SMART Board instead.   Problem solved. 

But thank you for your response.  I'm all set now.

Hi Lester,

Please close this discussion and if applicable accept and rate the same.



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