[Asterisk-Users] Cisco 7960 and short delay before voice starts after ring.

Andrew Gillham gillham at vaultron.com
Thu Mar 11 17:15:25 MST 2004

James Sizemore wrote:

>> exten => 6500,1,Answer
>> exten => 6500,2,Wait,1
>> exten => 6500,3,VoicemailMain2
>> Or should I say, "Me too!"
>> Is this the bug for the case in question?
>>  "CSCed48311: Media takes 0.4 sec to be set up"
>> Thanks.
>> -Andrew
> Yes the problem is that when making outgoing calls, there is enough of 
> a delay in the call setup once the remote side picks up, that people 
> that answer the phone "hello" will be heard saying "o"  or if they 
> talk fast enough not heard at all therefor leaving a very awkward 
> silence at the start of a call.

According to the bug release notes this is caused by the DSP setup on 
the 7960.  I would
guess that it must need to setup the correct codec once it is selected 
and that takes
some time (400ms apparently).

Perhaps they could create a 'leave the dsp setup for codec X and never 
change codecs'
config option. :-)

> This is very annoying. A earlier  person  suggested  answering the  
> calls before  dialing  and playing a ringing sound till the start of 
> the voice.  That may be a work around of sorts for some,  you will 
> hear a ring then a congestion tone on call that can't connect, or a 
> ring before a operator messages (say to dial one before the number) 
> that most users may not be used to.  I'll be playing with that ideal 
> to see what "odd" effect a ring has before call setup causes.
> The work around may be less annoying then the problem. <smile> I'll see.
Sounds good.  I have not been that bothered with it when I make a normal 
voice call.
It is mostly annoying when hitting the messages button on the phone.  My 
delay helped
that situation.

Perhaps on calls where asterisk is proxying the rtp stream we could have 
an option to
tell asterisk to open the connection to the 7960 before the connection 
is setup on
the other side of the call.  So the 7960 gets a head start.  It would 
force the codec
but that is fine by me, my G.729 is preferred and I don't mind asterisk 
since I have a low number of calls.


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