An improved automatic/remote RF instrument monitoring system including a plurality of transponders configured to operate with one of a plurality of parameter sensing instruments remotely located from an interrogate/receiver. The interrogate/receiver transmits RF transponder activation signals in the form of a tone modulated onto a carrier. In response to the activation signals, the transponders "wake-up" and transmit an RF transponder signal which is received and processed by the interrogate/receiver. The transponders include a transmission enable circuit which initiates transmission of the RF transponder signals at random times after receipt of the activation signals. The RF transponder signals are formed by a plurality of spaced transponder information packets. Transponder information packets of the transponder signal are transmitted at pseudorandom frequencies as a Manchester encoded bit stream including a preamble field of predetermined preamble data, an instrument parameter field of data sensed by the instrument, an instrument identification field of instrument identification data, and an error control code field of BCH error control code data.