This E.F. Johnson, UHF, half-duplex transceiver supported the 403-430, 430-450, 450-470, or 470-512 frequencies. The RF200 required an FCC frequency assignment and a frequency-matched antenna and cable. It was powered by the data logger or an external rechargeable 12 Vdc power supply (5 Ahr minimum capacity). E.F. Johnson model 3410