chan_dahdi

${ANI2}               * The ANI2 Code provided by the network on the incoming call.
                        (ie, Code 29 identifies call as a Prison/Inmate Call)
${CALLTYPE}           * Type of call (Speech, Digital, etc)
${CALLEDTON}          * Type of number for incoming PRI extension
                        i.e. 0=unknown, 1=international, 2=domestic, 3=net_specific,
                        4=subscriber, 6=abbreviated, 7=reserved
${CALLINGSUBADDR}     * Caller's PRI Subaddress
${FAXEXTEN}           * The extension called before being redirected to "fax"
${PRIREDIRECTREASON}  * Reason for redirect, if a call was directed
${SMDI_VM_TYPE}       * When an call is received with an SMDI message, the 'type'
                        of message 'b' or 'u'