Variables present in Asterisk 1.8 and forward:
${CDR(accountcode)} * – Account code (if specified)
${BLINDTRANSFER} – The name of the channel on the other side of a blind transfer
${BRIDGEPEER} – Bridged peer
${BRIDGEPVTCALLID} – Bridged peer PVT call ID (SIP Call ID if a SIP call)
${CALLERID(ani)} * – Caller ANI (PRI channels)
${CALLERID(ani2)} * – ANI2 (Info digits) also called Originating line information or OLI
${CALLERID(all)} * – Caller ID
${CALLERID(dnid)} * – Dialed Number Identifier
${CALLERID(name)} * – Caller ID Name only
${CALLERID(num)} * – Caller ID Number only
${CALLERID(rdnis)} * – Redirected Dial Number ID Service
${CALLINGANI2} * – Caller ANI2 (PRI channels)
${CALLINGPRES} * – Caller ID presentation for incoming calls (PRI channels)
${CALLINGTNS} * – Transit Network Selector (PRI channels)
${CALLINGTON} * – Caller Type of Number (PRI channels)
${CHANNEL} * – Current channel name
${CONTEXT} * – Current context
${DATETIME} * – Current date time in the format: DDMMYYYY-HH:MM:SS (Deprecated; use ${STRFTIME(${EPOCH},,%d%m%Y-%H:%M:%S)})
${DB_RESULT} – Result value of DB_EXISTS() dial plan function
${EPOCH} * – Current unix style epoch
${EXTEN} * – Current extension
${ENV(VAR)} – Environmental variable VAR
${GOTO_ON_BLINDXFR} – Transfer to the specified context/extension/priority after a blind transfer (use ^ characters in place of | to separate context/extension/priority when setting this variable from the dialplan)
${HANGUPCAUSE} * – Asterisk cause of hangup (inbound/outbound)
${HINT} * – Channel hints for this extension
${HINTNAME} * – Suggested Caller*ID name for this extension
${INVALID_EXTEN} – The invalid called extension (used in the “i” extension)
${LANGUAGE} * – Current language (Deprecated; use ${CHANNEL(language)})
${LEN(VAR)} – String length of VAR (integer)
${PRIORITY} * – Current priority in the dialplan
${PRIREDIRECTREASON} – Reason for redirect on PRI, if a call was directed
${TIMESTAMP} * – Current date time in the format: YYYYMMDD-HHMMSS (Deprecated; use ${STRFTIME(${EPOCH},,%Y%m%d-%H%M%S)})
${TRANSFER_CONTEXT} – Context for transferred calls
${FORWARD_CONTEXT} – Context for forwarded calls
${DYNAMIC_PEERNAME} – The name of the channel on the other side when a dynamic feature is used.
${DYNAMIC_FEATURENAME} The name of the last triggered dynamic feature.
${UNIQUEID} * – Current call unique identifier
${SYSTEMNAME} * – value of the systemname option of asterisk.conf
${ENTITYID} * – Global Entity ID set automatically, or from asterisk.conf
Variables present in Asterisk 11 and forward:
${AGIEXITONHANGUP} – set to 1 to force the behavior of a call to AGI to behave as it did in 1.4, where the AGI script would exit immediately on detecting a channel hangup
${CALENDAR_SUCCESS} * – Status of the CALENDAR_WRITE function. Set to 1 if the function completed successfully; 0 otherwise.
${SIP_RECVADDR} * – the address a SIP MESSAGE request was received from
${VOICEMAIL_PLAYBACKSTATUS} * – Status of the VoiceMailPlayMsg application. SUCCESS if the voicemail was played back successfully, {{FAILED} otherwise