Sec.  15.202   Certified operating frequency range.

   Client devices that operate in a master/client network may be certified if
   they have the capability of operating outside permissible part 15 frequency
   bands, provided they operate on only permissible part 15 frequencies under
   the control of the master device with which they communicate. Master devices
   marketed within the United States must be limited to operation on
   permissible part 15 frequencies. Client devices that can also act as master
   devices must meet the requirements of a master device. For the purposes of
   this section, a master device is defined as a device operating in a mode in
   which it has the capability to transmit without receiving an enabling
   signal. In this mode it is able to select a channel and initiate a network
   by sending enabling signals to other devices. A network always has at least
   one device operating in master mode. A client device is defined as a device
   operating in a mode in which the transmissions of the device are under
   control of the master. A device in client mode is not able to initiate a
   network.

   [ 70 FR 23040 , May 4, 2005]