I know it sounds weird, but here is what customer reports: In middle of the phone conversion tech will hear the sounds of siren, and not able to hear the person on the other side of the line. The other party hear silence for about 2min and then it comes back and party can hear each other. I cannot determine what is he referring as a “siren”. The sound similar to the police car or the sound generated from the network when call failed.

Wonder if there is any audio file on the device that may resemble this sounds. If not, then we know for sure that the sound is originated from the network.