Digital communications link - voice, data, and video at a 1.544 Mbps rate (24 64 Kbps channels)

Range of channels provided by T1 or E1 transmission service. A physical span is a group of channels taking up a single physical wire. A logical span is a group of channels taking up less than a single logical wire, or carried over more than one physical wire.

A digital communications link - voice, data, and video at a 2.048 Mbps rate; 30B/2D or 31B/1D (ISDN); non-North American version of T1.

Internet Protocol. Part of the TCP/IP family of protocols used to route messages and tracks the addresses of nodes.