49 C.F.R. § 220.31 Initiating a radio transmission.
Title 49 - Transportation
Before transmitting by radio, an employee shall: (a) Listen to ensure that the channel on which the employee intends to transmit is not already in use; (b) Identify the employee's station in accordance with the requirements of §220.27; and (c) Verify that the employee has made radio contact with the person or station with whom the employee intends to communicate by listening for an acknowledgment. If the station acknowledging the employee's transmission fails to identify itself properly, the employee shall require a proper identification before proceeding with the transmission.
Title 49: Transportation
PART 220—RAILROAD COMMUNICATIONS
Subpart B—Radio and Wireless Communication Procedures
§ 220.31 Initiating a radio transmission.
