These are the components of the ATC system:
· Top antenna
· Bottom antenna
· ATC coaxial switch (2)
· ATC/TCAS control panel
· ATC transponder (2).
The two antennas transmit signals from the ATC transponder and send received signals to the ATC transponder. These signals go through the ATC coax switches.
The ATC/TCAS control panel sends identification and control data to the transponders. The ATC/TCAS control panel also allows selection of either transponder 1 or transponder 2. The air data inertial reference units (ADIRUs) supply barometric altitude data to the ATC transponders.
The ATC transponders interface with the TCAS system. The ATC transponders send and receive suppression pulses through the suppression coax tees. This prevents ATC transmissions from interfering with the DME and TCAS system operations.