3Com Nbx 100 And Ss3 Nbx Administration Guide

Dial Plan Concepts and Overview31
Normally, you completely configure a dial plan before you start to use the 
system to control the telephones. Although you can make changes later, 
major changes in the dial plan can disrupt the system.
Decide whether you want to use a 3-digit or 4-digit dial plan before you 
create the dial plan, autodiscover, or manually add telephones or other 
devices to the NBX system.
When you import a dial plan, some parameters of the system change 
immediately. Others change only...

32CHAPTER 2: DIAL PLAN
CAUTION: If you configure the Auto Attendant so that it can access any 
external number, you risk the possibility of toll fraud. You can reduce the 
possibility of toll fraud by explicitly putting specific external numbers into 
the outgoing dial plan table. This precaution prevents outside callers from 
dialing any external number except the ones that you define.
There are two types of routes:
■Destination routes — Specify the extension of a destination device. 
They can also...

Dial Plan Concepts and Overview33
Hybrid Mode Operation Using the Dial Plan
If you map telephone buttons for some telephones but not others, you 
enable Hybrid mode (a mixture of standard and Keyset behaviors). The 
system provides a system-wide External Prefix setting, which allows the 
administrator to establish a prefix.
Off-Site Notification
The NBX system uses off-site notification to notify users when new voice 
mail messages arrive. You can define notification devices and assign them 
in the...

34CHAPTER 2: DIAL PLAN
Dial Plan TablesDial plan tables contain information that controls how the system routes 
calls. Each dial plan configuration file consists of at least three dial plan 
tables. This section discusses these topics:
■Dial Plan Command Format
■Internal Dial Plan Table — Must be table ID 1
■Incoming Dial Plan Table — Must be table ID 2
■Least Cost Routing Dial Plan Table — Must be table ID 3
■Adding New Dial Plan Tables
CAUTION:Tables 1, 2, and 3 must exist. Do not delete them. You may...

Dial Plan Tables35
Figure 2   Dial Plan Command Format
Ta b l e 6 describes each field of a dial plan command.
Table Create 1 Internal
/                  Id Entry  Digits       Min Max   Class          Prio Route
/
TableEntry Create   1     1  0              1   1   Internal          0     4
TableEntry Create   1     2  1              3   3   Internal          0     0
TableEntry Create   1     3  2              3   3   Internal          0     0
Table Create 2 Incoming
/                  Id Entry  Digits...

36CHAPTER 2: DIAL PLAN
If a new entry in the Internal table appears not to work, it is possible that 
the system is using an entry from the Least Cost table instead. To avoid 
such conflicts, you can accomplish least cost routing using only the 
Internal table. 3Com strongly recommends that, to keep the dial plan as 
simple as possible, you use only the Internal table for least cost routing.
For more information on how to use the dial plan configuration file, 
see “Managing the Dial Plan Configuration...

Dial Plan Tables37
Example: If Digits = 2, Min = 4, and Max = 4, the system knows that if 
the first digit is 2, it must collect no less than 4 and no more than 4 digits 
before making the call routing decision.
If the caller dials at least the minimum number of digits and not more 
than the maximum number of digits, the system waits 5 seconds and 
then routes the call based on the digits dialed.If the caller dials more than 
the maximum number of digits, the system attempts to place the call.
Often, Max...

38CHAPTER 2: DIAL PLAN
Internal Dial
Plan TableThe Internal dial plan table (table ID 1) defines how to handle calls placed 
from internal devices, such as NBX Business or Basic Telephones, to a 
destination. A destination can be another internal device, such as a local 
telephone, or an external telephone line (Analog Line Card or Digital Line 
Card) that connects the NBX system to other facilities.
The Internal dial plan table consists of a series of commands. For an 
example of the command format, see...

Dial Plan Tables39
Least Cost Routing
Dial Plan TableThe Least Cost Routing table (table ID 3) defines how to route calls in 
order to minimize the cost of those calls.
Example: You might use two different long distance carriers, one for a 
specific geographic region, and one for all other areas of the country. In 
the Least Cost Routing table, you can create entries that route calls 
differently for those two geographic areas. Each country uses a different 
method to accomplish this. In the United...

40CHAPTER 2: DIAL PLAN
Example: Users at site A dial 911 and the system uses the Internal table 
(table ID 1) to make the emergency call on one external telephone line. 
Users at site B dial 911 and the system uses table ID 4 to make the 
emergency call on a different external telephone line. The emergency 
staff know, based on the dialing number, which site has the emergency.
Enhanced 911, E911, is available in some areas. This service enables 
emergency staff to identify the specific location of the...