The setup is an 1861 with 5 IP phones. I am running version 12.4(22)T The receptionist is saying that when some calls come in from outside customers, she intermittently has a delay of 10 seconds before she can hear the caller's voice. What would cause this to happen? The config of the 1861 is attached. Thanks
What's the call flow?
It should be like this:
The Call Manager is located in my office. It is version 22.214.171.1240-3.
On CUCM, you can try two things:
On the H323 gateway:
Check MTP required
Enable Outbound Fast Start
Enable Inbound Fast Start
Sometimes we see long delays with H323 is required to do slow start.
Otherwise, it would require getting mgcp/pri debugs from the far end gateway, CCM traces, and H323/ccapi debugs from the 1861 - which is messy.