Code of Federal Regulations Title 47. Telecommunication § 47.95.1787 GMRS additional 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.

(1) Digital data transmissions may contain location information, or requesting location information from one or more other GMRS or FRS units, or containing a brief text message to another specific GMRS or FRS unit. Digital data transmissions may be initiated by a manual action of the operator or on an automatic or periodic basis, and a GMRS unit receiving an interrogation request may automatically respond with its location.

(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.