 Calls were not routed "up-chain" to Class 2 or Class 1 switches in a different region.Analog circuits between AT&T long-distance switches are known as Inter-Toll trunks while circuits from a long-distance switch to local switches are known as Toll Completing trunks or toll switching trunks.Trunks between long-distance switches in other carrier networks are known as Inter-Machine Trunks or IMT's.