Phone set A connected with Huawei ONT HG8121H further ONT connected with Huawei OLT MA5603T.
When B number (either Mobile phone or Landline phone) called to A number then B number hear echo noise.
Kindly collect the following infromation to locate the issue :
· Cover the phone transmitter at the peer end where echo occurs. The echo persists. Therefore, the echo is not the acoustic echo. If it is the acoustic echo, the echo disappears when the phone transmitter is covered. In addition, when the peer phone calls a phone connected to anther device, no echo exists. Therefore, the echo is generated by the ONU.
· Capture the H.248 signaling and analyze the signaling issued by the softswitch. It is found that the EC function is disabled. In the signaling, "tdmc/ec=off" indicates that the EC function is disabled. That is, no EC is implemented on the ONU, and therefore the peer subscribers can hear their own echoes.
· Modify the data configuration on the softswitch, that is, enable the EC function. Then, perform the test. It is found that the call is normal, and neither side can hear their own echoes.