Yes.  About 4 1/2 years after my mother's death, I was at work and had just dialed the number of one of the employees on our staff and when the connection was made, there was absolute silence on the other end.  Then I heard a woman's voice say very clearly and with normal talking volume "Hello, Linda".  I didn't say a word out of surprise, then a second later there was static on the other end and the person I was trying to contact came on and said "Hello?".  I asked him if there was anyone else there who had answered and he said 'no', he just picked up his phone and answered. 

In thinking about it afterwards, I realized the voice was low and sounded very much like my mother's, but of course, I can't be sure.  Very strange how that happened, though.