I'm facing an echo issue on my customer. He has 3 voice gateways running MGCP. Two of them have connections to PSTN, and one has a link to his NEC PBX.
The echo occurs on calls to PSTN or to analog phones on PBX, but it is intermitent. The weird thing is that it started something about 2 ou 3 weeks ago, and this IPT implementation has more than 3 years!
The echo cancel is enabled, and the coverage is already set to 64ms. Input gain and output attenuation is 0 for all ports. Remembering that the configuration is in Call Manager, since it's MGCP.
Should I change the values for input gain and output attenuation? For which value? Since this problem is intermitent, it's hard to make a change and test...
Does anybody have any ideas?