I never saw a TCAS unit installed that talked to the ground prox, then argued with each other over who took precidence. The fact is, each unit operates independently...one worries about traffic the other about terrain. Both can and will squak, and have squaked at me in the pattern at mountainous airports at the same time. The fact is if you have a flock of airliners above you, mountains below...the PILOT will have to make a decision, not the box.
Actually, that's precisely what TCAS II does.
With respect to the recent conversation on inhibited TCAS commands, my AOM includes the following information about certain functions:
Advisory Priority: Can revert to TA ONLY or STBY when higher priority advisories (e.g., GPWS, Windshear, etc) occur.
Altitude Climb Limit: Inhibited in accordance with aircraft performance limitations.
Descend RA: Inhibited below 1,000 feet in descent, and 1,200' in climb.
Increase Descent RA: Inhibited below 1,450'.
Resolution Advisories: Inhibited below 400' in descent and below 600' in climb. (TCAS automatically reverts to TA only)
--one might hope that with the demise of lookforshooter, the professional tone of the forum might be restored, but unfortunately he's already begun posting as nonflushinglav (strangely appropriate), and like his many other pseudonyms, has started his new posting career by agreeing with his old identity.