The RF310B is an RF modem used with our RF310, RF312, and RF313 narrow-band radios that usually resides at the computer site and serves as a link between field stations and repeater stations. It includes a 110/220 Vac to 12-Vdc transformer, an RF310M modem, an RS-232 port, internal mounts for an RF310-series transceiver, and a 7026 cable.