Leased lines services (or private Line services) became digital in the 1970s with the conversion of the Bell backbone network from analog to digital circuits. This allowed AT&T to offer Data phone Digital Services (later re-branded digital data services) that started the deployment of ISDN and T1 lines to customer premises to connect.[1]
An Internet leased line is a premium Internet connectivity product, normally delivered over fiber, which provides uncontended, symmetrical bandwidth with full-duplex traffic. It is also known as an Ethernet leased line, dedicated line, data circuit or private line.