If you have used a mobile phone for a while, you more than likely have experienced an echoing issue every now and again. An echo is when you can hear what you said a moment or two later in the speakers. This can be very distracting, and although the individual on the other line cannot hear it (it does not play through their speaker) you can, and you more than likely want to correct the issue.
Purchase a mobile phone with echo protection. Some wireless phones have the ability to block out this issue. However, this is an expensive fix and you more than likely do not want to buy a new phone.
Dial the phone number and listen for an echo. If you hear an echo hang up the phone (you should probably tell the other individual why you are hanging up first). The echo is caused by a failure to completely connect the two mobile phones together. With the weaker signal your phone begins to echo.
Dial the number again. This time the echo is gone, as long as a secure connection is created. The echo issue is something you can not predict and happens now and then. Disconnecting the phone call and re-dialling the number is the only way to correct the problem without purchasing an echo cancellation phone.