http://lamson-home2.com/WirelessChimes.php

under Extend-a-chimes
My best friend's mom had substantial hearing loss prior to her passing. This was the solution we picked. I took a few minutes to install the wireless transmitter in the chime assembly. We plugged the receiver / remote chime into a location where she was unable to hear the main chime. They came as a pair and we were able to find a stand-alone additional receiver / chime. They sound separate, programmable audibles for each door. This solution involves minimal wiring and gets the coverage needed without breaking the ear drums of a person near the main chime. We picked them up at the, "Save big money at", store.
Joe