annoying noise just before secondary dialtone with IP Phones?

[ADB100]

We have a customer with an MD110 and several IP Phones. Very occasionally when '9' is hit for an external call there is an annoying noise that I can only describe as a whip cracking or slap-back type noise is heard. This only seems to happen with the IP Handsets and is intermittent. I have verified the QoS settings on the Cisco switches they are connected to and I am happy with them.
It is only when the secondary dialtone is received as the initial dialtone when the handset is lifted or the speakerphone button is pressed is generated locally by the phone, once you hit '9' an RTP stream is set up and the secondary dialtone is received from the Gateway interface on the MD110.

Has anyone seen anything similar? As I say it is intermittent but is annoying especially if you have a headset on. There is also a delay to dialtone that I think may be related, possibly a firmware issue on the IP Phones?

Thanks

Andy

 

[whosrdaddy]

seems to me you are using G729AB codec

please give following printouts :

IPBOP:BPOS=ALL;
IPGKP:LIM=ALL;

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[ADB100]

I don't know the MDD110 at all........ I went to look at this issue from a Networking (Cisco) perspective, so I eliminated the Cisco element and can only suspect the Ericsson side now. That being said it definitely was G729 though as the Ethereal trace showed this in the H.323/H.245 protocol negotiations. I have suggested I re-visit with a MD110 IP Voice guy and try to look deeper.

Thanks for your reply, if I go back in soon I will take your suggested commands with me. What information do they generate?

Thanks

Andy

 

[whosrdaddy]

these commands give an idea about the settings of the IP boards in the MD110

-----------------------------------------------------
What You See Is What You Get
Never underestimate tha powah of tha google!