A dial plan establishes the expected number and pattern of digits for a telephone number. This includes country codes, access codes, area codes and all combinations of digits dialed. For instance, the North American public switched telephone network (PSTN) uses a 10-digit dial plan that includes a 3-digit area code and a 7-digit telephone number. Most PBXs support variable-length dial plans that use 3 to 11 digits. Dial plans must comply with the telephone networks to which they connect.
In the U.S., some typical dial plans include:
- Internal extension numbers of two, three, or four digits.
- Local numbers of seven or ten digits, which may be preceded by a 9 if required to access an outside line.
- Long distance numbers of eleven digits, consisting of a 1, then a three-digit area code, then a seven-digit number; preceded by a 9 if required.
- International numbers of any length starting with 011 and preceded by a 9 if required.
Syntax
The following syntax used to identify a dial plan in a digit map is adapted from [RFC 2705][page needed].
To specify a |
Enter the following |
Result |
|---|---|---|
| Digit |
|
Identifies a specific digit (do not use #) |
| Range |
|
Identifies any digit dialed that is included in the range |
| Range |
|
Specifies a range as a comma separated list |
| Wild card |
|
x matches any single digit that is dialed |
| Wild card |
|
. matches an arbitrary number of digits |
| Timer |
|
Indicates that an additional time out period of 4 seconds should take place before automatic dialing starts |
Some dial plan examples using the above syntax look as follows:
For calls to |
Users dial |
Dial plan |
|---|---|---|
| Internal Extension |
|
xx |
| Local Number |
|
9xxxxxxxT |
| Emergency |
|
911 |
| Local Operators |
|
90T |
| Long Distance |
|
91xxxxxxxxxx |
| International |
|
9011x.T |
See also
This entry is from Wikipedia, the leading user-contributed encyclopedia. It may not have been reviewed by professional editors (see full disclaimer)
