BTS abbreviated for Base Transiever Station is a collection of transmission and reception card designed for routing of signals from end user to msc and vice versa.

There are many types of BTS depending on the manufacturing companies viz nokia,ericcsion, zte,huwai etc ...i've worked on a few so can tell u about them

in nokia there is practically 2,2,2/4,4,4/8,8,8 configuration but this may vary depending upon the traffic requirement of the circle. mostly composite configurations are used, like 2,3,3 or 2,2,4 etc.

these nos are nothing but no of trx cards in each sector , for example 2,2,2 is 2 trx cards in each of three sectors.

power consumption also is different for each type of BTS, for NOKIA's Flexi indoor BTS running on 222 config power requiremnt will be approx 48 watts per hour

typically on every BTS 48V is supplied with negative polarity.

feel free to mail me for any further doubts