Polycom IP330 can not hear remote caller

[vokocomm]

We have IP330 behind DrayTek 2920 router.  After a couple days phones not used, the phone could lose registration.  In this case, when Polycom dial out, Polycom side can hear other person, but that person can't hear Polycom side talking. 

We have IPsmarx softswitch which is a Windows program software hosted at another data center.

On IP330 phone, I have Registration Expires set to 55 sec.

Where could I check into this problem? 

thanks,

dc

[SteffenBaierUK]

Hello dc,

welcome to the Polycom Community.

This sounds like a firewall / port range issue. Possibly you have not opened up enough ports to cover the whole RTP range.

A wireshark Trace would tell you by monitoring the traffic.

You should contact your Reseller for further support if you are unable to do so yourself.

Best Regards

Steffen Baier

Polycom Global Services

[vokocomm]

Thanks Steffen for pointing out RTP range possibility.

Could tell me Polycom RTP range so that I can make sure our FW open it up those?

This phone was working two days ago though.  Then got this problem can't hear each other after connected.

thanks,

dc

[SteffenBaierUK]

Hello dc,

the RTP Range is usually on our Phones as described => here <= on Page 330 starting with Port 2222

Quote:

RTP and RTCP can use any even port between 2222 and 2269 (2317 in VVX-1500), but this is configurable by setting  tcpIpApp.port.rtp.mediaPortRangeStart.

For further details please liaise with your Polycom Reseller.

Best Regards

Steffen Baier

Polycom Global Services