There are two levels of parameter evaluation done in the Asterisk
dial plan in extensions.conf.
- The first, and most frequently used, is the substitution of variable
references with their values.
- Then there are the evaluations of expressions done in $[ .. ].
This will be discussed below.
Asterisk has user-defined variables and standard variables set
by various modules in Asterisk. These standard variables are
listed at the end of this document.
lmadsen
2010-01-14