Direct distance dialing (
DDD) or direct dial is a telecommunications term for a
network-provided
service feature in which a
call originator may, without
operator assistance, call any other
user outside the local calling area. DDD requires more digits in the number dialed than are required for calling within the local area or
area code. DDD also extends beyond the boundaries of national public telephone network, in which case it is called
international direct dialing or international direct distance dialing (IDDD).