Administrator's Guide

Understanding the dial plan
Issue 5 October 2002 71555-233-506
Understanding the dial plan
Your dial plan tells your system how to interpret dialed digits. For example, if you
dial 9 on your system to access an outside line, it is actually the dial plan that tells
the system to find an external trunk when a dialed string begins with a 9.
The dial plan also tells the system how many digits to expect for certain calls. For
example, the dial plan may indicate that all internal extensions are 4-digit
numbers that start with 1 or 2.
Let us take a look at an example dial plan so you’ll know how to read your
system’s dial plan. The following figure shows an example of a simple dial plan.
The Dial Plan Analysis Table defines the dialing plan for your system.
The Call Type column in the Dial Plan Analysis Table indicates what the system
does when a user dials the digit or digits indicated in the Dialed String column.
The Total Length column indicates how long the dialed string will be for each
type of call. For example, this dial plan shows that when users dial a 5-digit
number that starts with 3, they are dialing an extension.
The Dial Plan Analysis Table in our example contains the following call types:
■ Attendant (attd) — Defines how users call an attendant. Attendant access
numbers can be any number from 0 to 9 and contain 1 or 2 digits.
In our example figure, the system calls an attendant when users dial 0.
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DIAL PLAN ANALYSIS TABLE
Percent Full: 9
Dialed Total Call Dialed Total Call
String Length Type String Length Type
0
1 attd __ _ ____
1
3 dac __ _ ____
3
5 ext __ _ ____
4
6 ext __ _ ____
5
7 ext __ _ ____
*
3 fac __ _ ____
#
3 fac __ _ ____