I have had the 10U for years and it has worked well. I haven't used it in over a year now and am trying to pair it with a new phone. I have done a factory reset. When I go into Configuration Menu, there are no choices for Phone Pairing, only:
Delete all pairings
Remote control pairing
Universal Intercom pairing
Factory reset
I successfully paired with an RC3 remote. I have deleted all pairings and did the factory reset. There simply is no choice for Phone pairing. I did connect via USB to my computer and updated the firmware to the latest.