Echo...Echoooo on MGCP

Unanswered Question
Mar 3rd, 2008

Does anyone have an idea as to what causes echo on FXO using MGCP? I read some conversations this morning on Ping times, is that part of it?

I have this problem too.
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rhugo Mon, 03/03/2008 - 11:51

it can be attributed to a lot of parameters, but the simplest method to start with is looking at your settings for input attenuation and output gain at the voice port level.


rule of thumb

start at 0 (default setting) and increase 2db at a time, with a MAX of 12db (anything HIGHER will cause problems with DTMF recognition


rule of thumb

same as above, start at 0db and increase at a rate of 2db at a time


•Avoid adding gain on the input side; it amplifies noise.

•Try to decrease the attenuation at the output side instead to raise an output level.

•If you are applying 0 dBm of attenuation and the signal is still too soft, go to the input side and increase the gain to avoid overdriving the inputs on your first attempt.

•To lower an output level, adjust the input side first; then adjust the output side.

and, as always with voice ports, do a "shut" / "no shut" to have changes take effect.

Here is an older link for the ICS7750 referencing this information:

Hope This Helps....

pharden Mon, 03/03/2008 - 13:00

Thanks for the info. The link says no go.

Forbinden Link.


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