TCAS vs TAS
 

One of the turbine types I fly is fitted with a TAS - Traffic Advisory System. That is for all intents and purposes a TCAS system except it does NOT give Collision avoidance information.

It will bark "traffic traffic" at you and show up in pretty colours, but that's it (no climb/descent instruction).

If I am head to head with a TCAS system, will your TCAS system show climb or descent instrucitons with the RA?

I am thinking no, but would like clarifiaction as I can't find that in the manual for it!

CS

CS, first, I'm not familiar with TAS. Somehow I doubt it is "for all intents and purposes a TCAS system ", since tcas systems talk to each other, for example to ensure one will give a climb command, and the other will give a descend command.
So if a tcas is head to head with a TAS, I expect it to treat the Tas aircraft like any other non tcas transponder aircraft. That is, the tcas aircraft will get a climb or descent to avoid.
Incidentally, the tcas will know the other aircraft does not have a tcas, and so the climb or descent will be issued earlier than if the two aircraft were both tcas equipped.
Hawk

We have a TCAS system (BF Goodrich TCAS791) which works the same as CS's, ie it tells us where traffic is, its altitude and whether climbing or decending, but does not give avoidance instructions.

That is TCAS I. TCAS II gives you a RA.