AT&T MERLIN LEGEND Communications System Release 2.0 Maintenance And Troubleshooting Manual page 208

Glossary
DTE
data terminal equipment
dual-tone multifrequency (DTMF) signaling
touch-tone signaling from telephones using the voice transmission path. The
code for DTMF signaling provides 12 distinct signals, each composed of two
voice-band frequencies.
E&M
ear and mouth (receive & transmit)
E and M signaling
Tie-trunk supervisory signaling, used between two communications systems,
in which information is transferred through two-state voltage conditions (on the
E and M leads) for analog applications and through two bits for digital
applications.
EIA-232-D
A physical interface, specified by the EIA (Electronics Industries Association),
that transmits and receives asynchronous data at speeds of up to 19.2 kbps
over cable distances of 50 ft (15 m).
electronic switching system (ESS)
A class of modern switching central office (CO) systems in which the control
functions are performed principally by electronic data processors operating
under the direction of a stored program.
expansion carrier
A carrier added to the control unit when the basic carrier cannot house all the
modules needed. An expansion carrier houses a power supply module and
up to six additional modules.
extended superframe format (ESF)
A framing format consisting of individual frames of 24 eight-bit slots and 1
signal bit (193 bits) in a 24-frame extended superframe. See also D4 framing
format.
FCC
Federal Communications Commission
GL-6 Glossary