In the keypad enrollment of tranmitters and in the walk test mode, the number of valid transmitter packets are decoded and announced about 8 seconds after the first valid packet is decoded. A GE door and window transmitter sends 8 data packets. If all eight packets are decoded, the M1 will announce "Radio Level 8". If noise or interference destroys some of the packets, a value less than 8 will be announced. This gives a relative signal strength of the transmitter and checks for proper decoding of the data. Should two valid transmitters transmit at the same time, the Radio Level announced could be up to 16 decodes, adding the total number of decodes together.
During the keypad enrollment of transmitters mode, the M1 tells the M1XRF receiver to accept all valid data packets whether it is enrolled in the M1 or not. You can then see the middle RXD LED blink when it sends the valid packet count to the M1 about 8 seconds from the first packet decode.
We tried using the RSSI signal strength coming out of the M1XRF but the level would shift when the automatic gain control switched in from a strong signal and resulted in the strong signal being seen as a medium signal strength or a weak signal being seen as stronger than it really was. We decided to use the packet decode method which works better.