I got it two used at a garage sale a while, and they work on the conventional channels 800MHz. I went out into the mountains to test them out where no one else would be using 800MHz range. From that I determined with my 396, I can only get 7 out of 8 channels that are transmitting a signal. It also has 8 tones both a mix of DPL & PL. And with my scanner I can not get the 8th tone with any channel, or the 8th channel on any PL or DPL. But the two TK's work just great communicating. Any idea of what this is? Some type of encryption?