If you deal with Voice over IP (VoIP), you must have come across this scenario at one time or another: A user complains that when they answer their phone, the caller can’t hear them, even though they can hear the calling party. Or, it may be that neither party can hear the other and there is just silence on the line.
This is the classic case of one-way or no-way audio, where a voice call is successfully completed, but either the voice packets only successfully travel in one direction, or neither end successfully receives voice packets. It may be difficult to understand why this happens, especially since the phone does ring, both physically for the called party and via the ring-back tone for the calling party. It seems counterintuitive that the transmission of voice packets could be unsuccessful if the call was successfully set up.
This is a scenario that comes up a lot on our tech support calls at TeleDynamics. Here we list four of the most common culprits of this issue and suggestions for how to tackle them.
