I just install the GEX-P20HD HD Radio unit to my Z110BT and everything is working but no sound. All my other inputs are getting sound. I have read thur the manels of both units and can not find anything to help. Is there something I am missing?

Make sure that you do not have the IP Bus cable reversed. They seem very specific about the direction that this cable should be used. IE Black into the reciever and blue into the Nav Unit. Hope this helps

On the HD Radio box, take the P-bus cable out of the hole its in and stick it in the correct one. There are only two