2+2+2 means, 2 transceivers per sector so the calls per sector is approx 16 simultaneously as other channels are used for BCCH.
if you say 2 dTRU per sector it is used on the 2206, 2106, 2207 and equivalent to 4 x TRUs per sector approximately 32 voice calls simultaneoulsy.
so for a full config RBS/BTS using dTRU 4+4+4 config can be made.
12 x 8 ~ 96 calls for the whole site… 32 per sector..