SV9300 - IP CCIS question 1

[phadobas]

I have a 9300 IP CCIS connected to an SV9500. The problem is that latency between the sites is 600ms (we are talking across the globe here)... So what's occurring is that when a call is initiated, and the far end answers, the first half second of speech is missed. In real world, the person picks up the phone and says "hallo", and the calling person doesn't hear this "hallo" and doesn't know that someone answered the call. This is because when the call is answered, an answer signal comes back allowing speech path to be established, which takes a little over half a second.

SO...

When we set up plain SIP between these two systems, we can send a 183 SIP response, which means session in progress, which is "early media" and opens an actual speech path even while the phone is only ringing. This way, when the person answers, the speech path is already there, and saying "hallo" will be heard by the calling person.
However, the speech quality of SIP doesn't match the speech quality of the CCIS, so we are trying to implement this "early media" concept on the IP CCIS.

IP CCIS essentially is built on SS7, which does have a provision for early media, which is enabled by changing some parameters in the ACM message.
This - in fact - does exist on the 9300 too.

CM31 has settings for backwards signals, one of which is "Address complete - set up speech condition".

Does anyone know how to work with this? Have some experience with this?

 

[jeremycw]

On the 9300, check CM35 048, 0 = Set up speech condition without waiting FW GII, should set up the speech without waiting for the ack which is the backward signal and would be for calls going into the 9300. Something similar would need to be set on the 9500 side for calls going the opposite direction but I'm not sure what that is at the moment.

 

[phadobas]

Wow! Looks like it solved the problem one way: I can now call to the 9300 and don't miss the first part of the call. But still trying to find how to make it work the other way: calling from the 9300...