Last digit "E" will be reserved for sector identification, may be 1,2,3,...so on, depending upon thenumber of sectors in a BTS.2. Next 3 digits "B", "C", "D" will be reserved for BTS number in a geographical zone (Digit "A") in aCity or MSC.It can have values between 001 to 999.But, if digit "A" is equal to 6 then, BTS number can not be more than 553.3. Most significant digit "A" will be reserved for geographical zone in a City or MSC.It can have value from 1 to 6.But, if digit "A" is equal to 6 then, BTS number can not be more than 553 in that particularzone.Advantage