The Collins TTR-4000 TCAS Transmitter/Receiver contains circuits for receiving, transmitting, signal processing (including computing), and interfacing with other components of the TCAS-4000 system. The TCAS-400 system aids the flight crew by detecting the presence of nearby aircraft and providing a warning when the proximity of that aircraft is determined to be a safety threat. The TCAS interrogates the transponders in the surrounding aircraft and uses the replies from those transponders to compute their flight path.

The TTR-4000 comes standard with Change 7 logic as well as an ability to upgrade to Change 7.1 logic on other variations. The TTR-4000 can be used in a fixed wing aircraft or a helicopter dependent on the part number. The TTR-4000 comes in a 4 MCU package that is 5.01 inches wide, 12.56 inches long, 7.62 inches high and weighs 17.7 pounds. The TTR-4000 operates in the altitude range of -1,000 feet to +55,000 feet and a temperature range of -55°C to +70°C.