Information Technology Reference
In-Depth Information
Table 6-4
Destination-Pattern Brackets Wildcard Examples
Key
To p i c
Pattern
Description
555[1-3]...
Matches dialed numbers beginning with 555, having 1, 2, or 3 as the fourth
digit, and ending in any three digits.
[14-6]555
Matches dialed numbers where the first digit is 1, 4, 5, or 6 and the last three
digits are 555.
55[59]12
Matches dialed numbers where the first two digits are 55, the third digit is 5
or 9, and the last two digits are 12.
[^1-7]..[135]
Matches dialed numbers where the first digit is not 1-7, the second and third
digits are any number, and the last digit is 1, 3, or 5.
These wildcards are most often used when creating dial-plans for PSTN access. Initially,
the most logical destination pattern choice for the PSTN may seem to be 9T (9 for an out-
side line followed by any number of digits). The problem with this is that Cisco designed
the T wildcard to match variable-length strings from 0-32 digits. When a user dials an
outside number, such as 14805551212, the router configured with the T wildcard will sit
silently and wait for the user to dial more digits. By default, the router will wait for addi-
tional dialed digits for 10 seconds, which is the interdigit timeout (also called the T302
timer). Although you can force the router to process the call immediately after dialing the
number by pressing the pound key (#), this is not something you would want to train all of
your users to do.
Creating a PSTN dialing plan using wildcards other than T is not extremely difficult, as
long as you think through the reachable PSTN numbers. Table 6-5 provides a sample PSTN
dial-plan that you could use in the United States.
Key
To p i c
Table 6-5
Sample PSTN Destination Patterns for North America
Pattern
Description
[2-9]......
Used for 7-digit dialing areas
[2-9]..[2-9]......
Used for 10-digit dialing areas
1[2-9]..[2-9]......
Used for 11-digit long-distance dialing
[469]11
Used for service numbers, such as 411, 611, and 911
011T
Used for international dialing
Note:
Although you can manually create an international dial-plan without using the T
symbol, doing so can become tedious.
Example 6-12 illustrates the configuration of a North American PSTN dial-plan on a
router. In this example, the T1 CAS voice port 1/0:1 is connected to the PSTN, and inter-
nal users must dial 9 for outside PSTN access.
