hi mohit
u have fired many question of good topic
well first to start with is DAC and EDAP
DAC is the value given to the BTS BOI card it is actually the clock count which require to synchronize with the external clock
that means our BTS synchronize withthe help of the DAC value
now
EDAP is very much in significance with the EGPRS feature
as with EDAP u can dedicate TS to handle the packet traffic so when we do Packet transfer then most of the traffic is hold by the EDAP slots and the rest of the STS of the trx where EDAP is defined can be used to handle other calls
and witht he security point of view also it is beneficial
try to go through its details on net if still there is any querry
u r welcome to fire it here
bye