Leased Line - History

History

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 conversion allowed AT&T to offer Dataphone Digital Services (later re-branded digital data services) that started the deployment of ISDN and T1 lines to customer premises to connect.

Leased lines were used to connect mainframe computers with terminals and remote sites, via IBM Systems Network Architecture (created in 1974) or DECnet (created in 1975).

With the extension of digital services in the 1980s leased lines were used to connect customer premises to Frame Relay or ATM networks. Access data rates increased from the original T1 option up to T3 circuits.

In the 1990s with the advances of the Internet, leased lines were also used to connect customer premises to ISP Point of Presence whilst the following decade saw a convergence of the aforementioned services (frame relay, ATM, Internet for businesses) with the MPLS integrated offerings.

Access data rates also evolved dramatically to speeds of up to 10Gbit/s in the early 21st century with the Internet boom and increased offering in long-haul optical networks or Metropolitan Area Networks.