AT&T System 75 Wiring Diagram page 332

Digital Multiplexed Interface (DMI)
Specifies the remote interface requirements for multiplexed data
communications between a host computer and a private switching
system.
Digital Trunk
A circuit in a telecommunications channel designed to handle digital
voice and data.
Distributed Communications System (DCS)
A network of two or more switches, each with its terminals and
trunks, configured to function as a single large system.
Electronic Tandem Network (ETN)
A special tandem tie trunk network that has automatic call routing
capabilities based on the number dialed and most preferred route
available at the time the call is placed. Each switch in the network is
assigned a unique private network office code (RNX), and each voice
terminal is assigned a unique extension number.
Enhanced Private Switched Communications Service (EPSCS)
A private telecommunications network that provides advanced voice
and data telecommunications services to companies with many
locations.
External Call
A connection between a system user and a party on the public
telephone network or on a tie trunk.
Facility
A general term used for the telecommunications transmission
pathway and associated equipment.
CHAPTER 6. GLOSSARY
6-3