About echo in voice network, how does the input gain and output attenuation parameters affect echo?
And also about the value of ERL worst case (Echo return loss). If I define and ERL of 3 db does this means my my voice gateway would not be able to detect echo with ERL above 3dB (let's say 4dB ERL) for example
This needs a ton of explanation. However, i have found a very document which can help you in finding a lot of your answers.
Well, ask yourself first what generates echo. It has to do with signal feedback and often impedence mismatch.
So changing those details will affect how much echo you tend to see. The values will vary based on your signals from CO and specific equipment as well.
a 3dB variation by way is double the "volume" of the related signal.