I believe the radios are 1W output - not part 15 but authorized license free on the 900 MHz ISM band. Here's a link to Motorola's version: http://www.motorola.com/DTR/
Everybody uses the same frequencies. The channels are really digital codes.
My first info on similar devices in this band was about 2 years ago - a professional grade wireless microphone.
I question the FAQ that says as many as 10,000 radios can operate simultaneously within range of each other. Perhaps if the communicators are close enough to have strong signals.