03-02-2012 08:25 PM - edited 03-16-2019 09:54 AM
Hi
We have received feedbacks that making outgoing ISDN calls via PSTN voice is soft.
Have increase the input gain on the mgcp trunk but it seem like little improvement.
Would like to determine the isolation of this issue ? How to ensure that within the CCM, gateway are all ok and if there is any other way to capture information which can determine is on the service provider end having the issue ?
Thanks
03-04-2012 08:59 AM
All calls produces a low volume? And which side has the low volume? Have you checked "show controllers T1/E1" for errors ?. And more importantly, have you judged the call volume with your own ears ?
03-04-2012 04:05 PM
Just to get us started: gain/attenuation changes only take effect following a controller/interface shutdown. A reset is not sufficient.
Following that Paolo is on the right track here: it matters what direction of audio is quiet: PSTN to PBX (inbound) or PBX to PSTN (outbound). You need to find a number to reproduce this with before modifying the gain/attenuation. Some PSTN destinations - or callers for that matter - will be quieter than others; a byproduct of 100-year old infrastructure and electrical distortion over distance. Don't discredit soft-spoken people or a bad headset either; make sure you are chasing a legitimate problem here!
Once you've got an agreed upon and repeatable problem you should use caution modifying the gain/attenuation commands. This is a delicate balancing act and creating an imbalance will cause echo! The echo canceler relies on a delta in electrical signals between the transmit and receive paths to find echo and suppress it. Modifying the gain/attenuation directly influences that delta. Read this document to understand what you're modifying: http://www.cisco.com/en/US/tech/tk652/tk698/technologies_tech_note09186a0080149a1f.shtml
03-05-2012 01:13 AM
I wish I had Jonathan's eloquence sometime ...
Rated!
03-05-2012 02:40 AM
No errors on show controllers E1
The soft volume from CCM to PSTN, the agents will received soft volume
MGCP a need for shutdown/no shutdown ?
Trunk service providers isolated them from equipments all tested volume ok.
Have raised a TAC case on this issue
Will update the findings and sharings
Thanks for the information
Discover and save your favorite ideas. Come back to expert answers, step-by-step guides, recent topics, and more.
New here? Get started with these tips. How to use Community New member guide