Lines Labeled For Key System Telephones - AT&T MERLIN LEGEND System Reference Manual

Functional Description
Line Access
4-8 Modes of Operation
Ground-start lines can be used on a Key system only by designating channels
on a 100D module as ground-start lines. These are called emulated ground-start
lines. No ground-start lines from the telephone company can be directly
connected to a control unit registered as a Key system (FCC "KF" classification).
The following features are not available on a Key system:
t r u n k p o o l s
Automatic Route Selection (ARS)
queued call consoles (QCCs) and associated features
System Access buttons
In the Key mode, each outside line must be assigned to a line button on at least
one telephone. Because of this, multibutton telephones are the most common
telephones used in the Key mode (see Figure 4-2).
Figure 4-2

Lines Labeled for Key System Telephones

A user selects an outside line by pressing one of the line buttons labeled with a
telephone number (Personal Line button). Upon hearing a dial tone, the user
can dial out. When a line is in use, the green light emitting diode (LED) goes on
next to the corresponding Personal Line button on all telephones that share the
personal line.
The telephones in a Key system also have intercom buttons (labeled as ICOM)
that allow users to call other people connected to the system. An inside talk path
is provided when an intercom button is pressed. The dial tone that the user
hears can be programmed as an inside (the factory setting) or outside dial tone.