Does anyone know if TCAS2 and T2CAS is the same?
Not quite.
TCAS2
Traffic Collision Avoidance System (version) 2
T2CAS
Traffic (and) Terrain Collision Avoidance system
The 2 is for 2 Ts. It is a system that combines a TCAS2 and GPWS into one box and is made by ACSS. The GPWS has a predictive "forward looking" capability similar to EGPWS (which is a Honewell trademark) as well as some other clever features.
More on t2cas at
ACSS