Hi, Despite much searching, I can't find anything quite like the problem we seem to be experiencing with our recently activated asterisk pbx. Of four people answering several calls per five minutes, I have reports of the occasional call starting with dead air. The user picks up the call from the queue, and they can hear that the line is too quiet. If they start talking, the caller either doesn't hear them, or only hears the end of the first sentence. Reports are that this silence at the start of the call lasts from 4-5 seconds, sometimes over 10 seconds and more rarely over 20 seconds. After the period of silence the call proceeds with no further problems. I have taken packet dumps of extended periods, there is nothing consistently different about the calls with silent start compared to those without the problem. The SIP INVITE is sent to the phone, the phone rings, and OK's the call. The RTP stream begins straight away. I'm using cvs-head as of 2004-06-10, CVS-D2004.06.09.14.00.00, recently updated from v1-0_stable dated a few weeks before. This problem existed with both versions. The phones are Cisco 7960's with SIP image 6.3, the calls are incoming on an E1 connected to a TE410P. Calls are queued and the phones statically defined as agents in the queue which has a ringall strategy. There is no queue announcement played to the answering user. Asterisk in vvv verbose doesn't log anything different when this occurs. So, has anyone else heard of something like this? Or have a suggestion for further investigation? Cheers. -- -- Sam Tilders sam@jovianprojects.com.au (Move to Jupiter)
Chris Glover
2004-Jun-24 05:45 UTC
[Asterisk-Users] Dead air on 7960 sip at start of call.
Hi, I've noticed the same thing with my 7960 running SIP 7.1. I came to the conclusion that the Cisco does some clever echo cancellation, and that pause is the echo canceller training. I don't think it's an Asterisk problem. My Grandstream 101 works perfectly. Chris -- Chris ---------------------------------- E Mail: chris@glovercc.clara.co.uk SIP: 84411389@voiptalk.org IAXTEL: 17003366726 On Thu, 24 Jun 2004, Sam Tilders wrote:> Hi, > > Despite much searching, I can't find anything quite like the problem > we seem to be experiencing with our recently activated asterisk pbx. > > Of four people answering several calls per five minutes, I > have reports of the occasional call starting with dead air. > > The user picks up the call from the queue, and they can hear that the line > is too quiet. If they start talking, the caller either doesn't > hear them, or only hears the end of the first sentence. > > Reports are that this silence at the start of the call lasts > from 4-5 seconds, sometimes over 10 seconds and more rarely over > 20 seconds. > > After the period of silence the call proceeds with no further problems. > > I have taken packet dumps of extended periods, there is nothing consistently > different about the calls with silent start compared to those without the > problem. The SIP INVITE is sent to the phone, the phone rings, and OK's the > call. The RTP stream begins straight away. > > I'm using cvs-head as of 2004-06-10, CVS-D2004.06.09.14.00.00, recently > updated from v1-0_stable dated a few weeks before. This problem > existed with both versions. > > The phones are Cisco 7960's with SIP image 6.3, the calls are incoming > on an E1 connected to a TE410P. Calls are queued and the phones > statically defined as agents in the queue which has a ringall > strategy. There is no queue announcement played to the answering user. > > Asterisk in vvv verbose doesn't log anything different when this occurs. > > So, has anyone else heard of something like this? Or have a suggestion > for further investigation? > > Cheers. >