Severe Audio Static connecting to Polycom HDX series endpoint

[toddmorisak]

Greetings,

I am looking for insight on the following issue.

We experience severe (and immedate, upon connection) levels of audio static when a Cisco endpoint (SX20 or C40) connects to a Polycom HDX endpoint.  The Cisco endpoints are running TC7.2.1.  This does not occur when connecting from the Cisco endpoint to a Polycom VSX endpoint.

Furthermore, if the HDX endpoint dials out to a Cisco endpoint there are no issues.  This only happens when dialing from Cisco endpoint to HDX.  All connections are being made via H.323 not SIP.

All units are registered to the same VCS Control appliance.  The VCS is running X8.5.1, and is showing no errors or issues.

Any thoughts would be appreciated.

Thank you,

-TM

[Charles Hill]

Is static heard on both ends?

can conversation still be heard over static?

[toddmorisak]

Charles, thanks for your reply.

Good question, sorry I wasn't clearer above.  The static is only heard on the HDX system, audio on the Cisco unit from the HDX is fine.  The static is so severe that the connection has to be terminated quickly.  No functional audio can be heard over the static, though I suppose it could be there.

[lukepeverley · Accepted solution]

This is a bug in TC7.2.1

See here

CSCuq94402

CSCur78783

Symptom
Get white noise for audio and no video

Condition
Use TC7.2.1 and Polycom with software later than 3.0.5 and call using H323 with encryption enabled.

Workaround
Disable encryption, call using SIP, downgrade to TC7.1 or earlier Polycom release or wait for TC7.3.0 and set xConfiguration H323 Profile 1 Encryption KeySize: Max1024bit

We disabled encryption until TC7.3.3 is released.

7.2.1 is causing C20 models to restart mid-call

7.1.4 has shellshock vulnerability

[toddmorisak]

Thanks very much for the information.  This certainly sounds like the problem we are experiencing.

We are checking it out now, and will be doing additional testing in the next 24 hours.  I will report back after testing is complete.

[Wayne DeNardi]

What software version are you running on the Polycom devices - you've mentioned that your Cisco kit is pretty well up to date - what about the Polycom end?  There were a number of audio fixes in the newer releases of Polycom HDX software - we're currently on 3.1.6 on the HDXes we support and don't have any issues with calls with our Cisco fleet.

Wayne
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[toddmorisak]

Wayne, thanks for your reply.

Right now the HDX systems I have tested with are running 3.1.4-43132.  I will see if we can update those systems to the latest release.  (Most of the Polycom systems here are being phased out and replaced with new SX20 units.   However, it will take some time.)

[toddmorisak]

Just wanted to let everyone know that having encryption enabled seems to be the root cause of the problem.

We successfully tested between the Cisco and HDX units this morning, with encryption disabled, and we did not encounter the problem.

We are now in the process of changing/updating the endpoint software as a (hopefully) permanent solution to the problem.

Thanks again to everyone that offered insight into the issue.