Setting and Substituting Channel Variables
Parameter strings can include variables. Variable names are arbitrary strings. They are stored in the respective channel structure.
To set a variable to a particular value, do:
You can substitute the value of a variable everywhere using ${variablename}.
Here is a simple example.
In the second line of this example, Asterisk replaces the ${COUNT} text with the value of the COUNT variable, so that it ends up calling SayNumber(3).
For another example, to stringwise append $varname2 to $varname3 and store result in $varname1, do:
There are two reference modes - reference by value and reference by name. To refer to a variable with its name (as an argument to a function that requires a variable), just write the name. To refer to the variable's value, enclose it inside ${}. For example, Set takes as the first argument (before the =) a variable name, so:
The above dialplan stores to the variable "varname1" the value "varname2" and to variable "varname2" the value "value".
In fact, everything contained ${here} is just replaced with the value of the variable "here".