Thank u friends for ur response. I hope that all the vendors design the switches with common principle. We r working in both AXE10 & AXE810 type of exchanges. As I’m dealing with Ericsson, i can assure that Eric has a very good modular structure in both h/w & s/w.I hav doubts in dimensioning of the BSC whether it is finialised by bo. of TRU handling capacity or others. kindly help me.