47 CFR 95.29 - Channels available.
(a) For a base station, fixed station, mobile station, or repeater station (a GMRS station that simultaneously retransmits the transmission of another GMRS station on a different channel or channels), the licensee of the GMRS system must select the transmitting channels or channel pairs (see § 95.7(a) of this part) for the stations in the GMRS system from the following 462 MHz channels:
(b) For a mobile station, control station, or fixed station operated in the duplex mode, the following 467 MHz channels may be used only to transmit communications through a repeater station and for remotely controlling a repeater station. The licensee of the GMRS system must select the transmitting channels or channel pairs (see § 95.7(a) of this part) for the stations operated in the duplex mode, from the following 467 MHz channels:
(f) Except for a GMRS system licensed to a non-individual, a mobile station or a small base station operating in the simplex mode may transmit on the following 462 MHz interstitial channels:
(1) Only voice type emissions may be transmitted;
(2) The station does not transmit one-way pages; and
(3) The station transmits with no more than 5 watts ERP.
(g) Fixed stations in GMRS systems authorized before March 18, 1968, located 160 kilometers (100 miles) or more from the geographic center of urbanized areas f 200,000 or more population as defined in the U.S. Census of Population, 1960, Vol. 1, Table 23, page 50 that were authorized to transmit on channels other than those listed in this section may continue to transmit on their originally assigned channels provided that they cause no interference to the operation of stations in any of the part 90 private land mobile radio services.