A method of sending the value of a status variable from a sending device to a receiving device as part of a standardized binary coded radio message. The message includes fields for predetermined information to be sent with the message as well as a buffer field. The method includes causing the sending device to assemble, calculate a checksum for, digitally store and periodically transmit a predetermined type of message in the form of a radio signal readable by a receiving device. The status variable is not related to the predetermined information. Before the checksum is calculated, the sending device inserts the value of the status variable in binary coded format into the message in a buffer field. According to a governing messaging standard, the buffer field is not intended to transmit information. The receiving device interprets the binary value as the value of the status variable.