Telephone main line
Standard telephone main lines increased by the number of ISDN nodes.
1. The concept of "standard telephone main line" refers to the term used until 1999 of "fixed-line telephony subscriber" (i.e., an entity being a party to an agreement with an operator for the rendering of telephone services). 2. ISDN - integrated digital telephone network allowing the same network to be used for voice, video, fax and data transmission.