Synopsis:
Extension
manipulation lets you influence dialed numbers to create a more dynamic dial
plan.
How To Use:
The number
dialed is matched against rules that manipulate the number to produce a new
number. The new number is further processed as if it where the original number
dialed with the exception that it must be matched at the next priority level
from which it was created.
For example,
lets say the first priority of extension XXX is to strip the leading digit;
then, the resulting number would be matched at the second priority level of XX.
If there is no
match for the new number then it is treated as though an invalid number was
dialed.
Asterisk
provides applications for removing digits (StripMSD and StripLSD) and for
adding digits (Prefix).
StripMSD
removes leading digits while StripLSD removes ending digits. In both cases the
number of digits stripped is specified.
So for example,
the number 5551212 when stripped of its leading three digits with StripMSD
becomes 1212 and when striped of its ending four digits with StripLSD becomes
555.
Syntax:
exten =>
_[Extension],[Priority],[Application],[Count]
|
Extension |
- Number that
must be matched. |
|
Priority
|
- Order of
evaluation within rule set. |
|
Application |
- StripMSD or
StripLSD. |
|
Count |
- Number of
digits to strip. |
Example (StripMSD - Using 9 to reach an outside line):
A common use of
stripping is to remove 9 from an internally dialed number before routing the
call to an outside line.
exten
=> _9NXXXXXX,1,StripMSD,1
exten
=> _NXXXXXX,1,Playback,MustDialNineFirst
exten
=> _NXXXXXX,2,Dial,Zap/1/BYEXTENSION
Here the first
rule strips 9 from the number resulting in NXXXXXX. The new number then matches
with the third rule and the call is routed to an outside line. The second rule illustrates that if a 9
where not dialed first then a message is played instructing the caller to do
so.
Prefix appends
digits to the beginning of an extension. So for example, the number 1212 when
prefixed with 555 will become 5551212.
Format: exten => _[Extension],[Priority],[Application],[Count]
|
Extension |
- Number that
must be matched. |
|
Priority
|
- Order of
evaluation within a rule set. |
|
Application |
- Prefix. |
|
|