AT&T Partner II - Manual (Page 96)

Intercom call
Outside call
Primary line
Secondary line
Standard
phone
A call that is made using the [ Intercom ] button on an MLS- or
MLC-model telephone, to call another system extension
without tying up primary Centrex lines.
A call made from outside the Centrex system to an extension
within the Centrex system, or from inside the Centrex system
to a number outside the Centrex system. If your Centrex
system uses a dial-out code (usually a “9”), you must dial it
before you dial an outside telephone number.
The main Centrex line assigned to an extension, generally
used to place and receive all calls for that extension. When a
caller dials a phone number, the call rings immediately at the
extension where the line is assigned as a primary line (unless
line ringing is changed to let a user at another extension
screen calls on the line). See also Secondary line.
A line assigned to an extension for call coverage purposes,
generally with delayed or no ringing. When a call comes in
on the line, it rings first at the extension where it is assigned
as the primary line; only if there is no answer does it ring at
the extension where it is a secondary line. See also Primary
line.
An industry-standard touch-tone or rotary phone such as you
might have in your home. Some standard phones include
special feature buttons for frequently-used calling functions.
MLS- and MLC-Model Telephones
MLS-and MLC-model telephones have some buttons and indicators in common.
Refer to pages 6-4 and 6-5 for an explanation of where they are and how they
work. Call handling instructions for MLS- and MLC-model telephones and
industry-standard phones begin on page 6-12.
Ringing Patterns and Dial Tones
Your Centrex system determines the ringing pattern you will generally hear when
calls ring at your phone. (For example, there may be different ringing patterns
for inside and outside calls.) If someone makes an intercom call to your phone,
you will hear a ring and a beep (ring BEEP . . . ring BEEP . . . ring BEEP . . .).
When making most calls, you will hear the Centrex dial tone, indicating that you
are connected with a Centrex line. (If you press [ Intercom ], you hear the intercom
dial tone. See Appendix B for information on using the intercom button.)
6-2 Using Telephones