Each hand-held portable unit transmitter type submitted for certification under this subpart is subject to the rules in this section.

(a) Digital data transmissions. GMRS hand-held portable units that have the capability to transmit digital data must be designed to meet the following requirements.

(1) Digital data transmissions must only be initiated by a manual action by the operator, except that GMRS units may automatically respond with location data upon receiving an interrogation request from another GMRS or FRS unit.

(2) Digital data transmissions must not exceed one second in duration.

(3) Digital data transmissions must not be sent more frequently than one digital data transmission within a thirty-second period, except that a GMRS unit may automatically respond to more than one interrogation request received within a thirty-second period.

(4) The antenna must be a non-removable integral part of the GMRS unit.

(5) GMRS units must not be capable of transmitting digital data on the 467 MHz main channels.

(b) [Reserved]