A BCF controls the whole site that is you can stop the whole site from transmitting MML = ZEFS:23:L;). A BTS is a cell within the BCF (site) you can lock a BTS down (ZEQS:BTS,21:FHO,30:L;)and the rest of the BTS’s stil transmit.
There are usally 3 BTS to 1 BCF, so on a Nokia site build it may look like this:
BCF 21
BTS 21 (cell 1)
BTS 22 (Cell 2)
Bts 23 (Cell 3)
So locking BTS 21 (Cell 1) could only stop cell 1 from transmitting
A cell can have from 1 to 12 TRX in it