I am a relative beginner regarding wireless communications protocols and I am looking into the protocols used by toy helicopters, in particular the Hubsan X4. According to more experienced people who have done similar work the X4 uses "an A7105 transceiver chip".
Now according to the A7105 specification (pages 1 and 5), the A7105 runs on the 2.4GHz band, and is suitable for "2400 ~ 2483.5MHz ISM Systems".
Returning to my original source, he describes the binding mechanism of the helicopter:
First the Tx scans the RSSI on the following channels and picks the best one:
14 1e 28 32 3c 46 50 5a 64 6e 78 82 [HEX]
I was under the impression that the 2.4GHz band had only 14 bands (Wiki), so how can there be 130(+) channels for the helicopter to search through?