Certainly the challenge is out to everyone if they can show a TCAS unit coupled to Ground Prox and Radar Altimeters...
Oh Dear, the following is from the 747-400 Maintenance Manual(my highlighting).
The dedicated components of a TCAS system consists of:
• A TCAS computer
• A top directional antenna
• A bottom antenna,
- which may be either omnidirectional or directional, depending
on the flight phase.
The TCAS system interfaces with:
• The ATC system;
- L and R ATC Mode S transponders,
- top and bottom ATC antennae and
- ATC/TCAS control panel.
• Integrated display system (IDS)
• Modularised avionics and warning electronics assembly
(MAWEA)
The system makes use of interfaces with:
• Left and Right Radio Altimeters
• Ground Proximity Warning Computer (GPWC)
• Landing gear module
• Air/ground relays
• Left and Right Distance Measuring Equipment (DME)
• L and R central maintenance computer (CMC’s)
• Data management unit (DMU)
The TCAS II computer is a receiver/transmitter unit which contains
the processors required to determine if the path of nearby airplanes
will intersect the flight path of the TCAS equipped airplanes.