I can't get hearing aid compatibility (HAC) of my RAZR HD MAXX to work. It is supposed to make the phone communicate directly with the hearing aid, which in turn makes adjustments for better hearing.
HAC is turned on with the check box in the phone app settings. There might be some undocumented setting or condition that must exist for it to work.
The hearing aids brand is by Resound, model Verso 962. The HAC feature in the hearing aids is called Telecoil and is set to on. I can activate it manually by putting a magnet next to my ear.
A thread on a Motorola forum discusses getting HAC to work with RAZR M -- which has the same specification as the RAZR HD MAX: