The KTR-909 is a UHF transceiver providing 2 way voice and data communications in the frequency range of 225-399 MHz in 25 kHz increments. The KTR-909 is controlled by a KFS-599A control unit.

The KTR-909A is functionally equivalent to the KTR-909. However, the KTR-909A can be controlled by either a Radio Management Unit (RMU) via ARINC 429 interface or the KFS-599A.

The KTR-909B includes all of the features of the KTR-909 and KTR-909A but is controlled by the KFS-599B control unit or RMU with ARINC 429 interface. The KTR-909 may also be configured to tune some ADF systems. The main difference between the KTR-909/909A and KTR-909B radios is that the KTR-909B includes a second receiver fixed at the internationally recognized 243.000 Mhz emergency guard frequency. The “guard” receiver provides continuous monitoring of 243 MHz while simultaneously receiving main receiver.

It should be noted that 243 MHz is military reserved emergency UHF radio frequency. Therefore, radios containing this guard receiver (as detailed above) are considered export restricted military items controlled by the U.S. Department of State. An export license from the Dept of State is required for any exports of the KTR-909B radio.