Recently i am using Grandstream UCM 6202 to divert calls through a SIP Provider (Hoiio)
but i am facing this issues
me as the caller, the call quality is good. i am able to hear the other side quite well
but for the person receiving the call, they mentioned that there is a distortion in the call.
the call route is roughly as shown
Caller > Grandstream UCM > Hoiio > Receiver
when i bypass grandstream, there is no distortion on the calls it self
so most likely it should be the grandstream configuration issues
i checked hoiio setup, the CODEC they are using is G.729, GSM, G.711A, G.711U
under grandstream, i tried to add all these 4 CODEC but i am still facing with this issues
i’ve tested on the network portion, it should not be caused by network issues
anyone know what could be causing this distortion issues?