There is an confirmed issue where the panel gives an error for no available 900MHz radio channel.
The panel/XCVR2 should support pairing/learning of (4) TS1's*; (3) Image Sensors; (1) Go!Bridge IP communicator, but instead gives the "no available channel" error on attempting to install a 900MHz device.
This issue has been reported on panels where (3) Image sensors are already paired/learned. (e.g., if you already have three Image Sensors, you cannot pair/learn the bridge. So, to sucessfully pair/learn the bridge, you must unpair/remove an Image Sensor. You can either have (3) Image Sensors, or (2) Image Sensors and the Bridge)."No available Radio Channel for this Device Type- Please refer to the installation manual to determine the limits and prerequisites for 900 MHz devices."
* Q4 keypad limitation is (4) regardless of whether or not they are PAD1, or TS1 (or combination thereof).