Lucent Technologies MERLIN LEGEND 5 - Manual (Page 385)

About Telecommunications
Page B-1 Telephone Extension Equipment
B
MERLIN LEGEND Communications System Release 5.0
System Manager’s Guide
555-650-118
Issue 1
June 1997
B
0
About Telecommunications
Many of the terms and concepts involved in telephone communications have
been in use since Alexander Graham Bell made the first phone call in 1876.
Because understanding them will help you to understand how the system works,
this section contains a brief history and description of telephone communications.
Basically, telephone communications involves four elements:
■ Telephone Extension Equipment (also referred to by an older term,
telephone station equipment). The telephone instrument and/or other
equipment (for example, a fax machine) used to transmit and receive the
telephone signal.
■ Transmission Facilities. The equipment and media (for example, wire,
cable, and optical fiber) that provide the communications path that carries
the telephone signal.
■ Switching Equipment. The equipment that makes the electrical cross
connections so that the caller is connected to the called party.
■ Signaling. The transmission of information that controls the network, for
example, alerting the switch that a user wants to make a call, transmitting
the telephone number of the called party, and alerting the called party of
the call. Signals also tell the switch about how to make the connections.
This appendix provides information about each of the elements.
Telephone Extension Equipment 2
Telephone extension equipment is the user’s gateway to the global
communications network and an array of services. While today’s telephones
range from single-line telephones to multiline telephones with various features
and options, telephone extension equipment can now also involve such things as