All calls to and from the extension is fine but when PSTN call is received there is noise. However I can make calls OK. In the configuration, the pstn line is plugged to FXO2 and forwarded to the extension. I ran the FXO diagnostics and it ran OK and suggested updating the fxocfg.cgi, which I did but this did not solve the problem. I am new on the QuadroM8L and any pointers much appreciated.