Synopsis:

 CHANNEL(item)

Description:

 Gets/set various pieces of information about the channel.  (New in 1.4)

item may be one of the following:

Read/write	Item	Description
R/O	audioreadformat	format currently being read
R/O	audionativeformat	format used natively for audio
R/O	audiowriteformat	format currently being written
R/W	callgroup	call groups for call pickup
R/O	channeltype	technology used for channel
R/W	language	language for sounds played
R/W	musicclass	class (from musiconhold.conf) for hold music
R/O	state	state for channel
R/W	tonezone	zone for indications played
R/O	videonativeformat	format used natively for video

Items available in 1.6:
Standard items (provided by all channel technologies) are:

Read/write	Item	Description
R/O	audioreadformat	format currently being read
R/O	audionativeformat	format used natively for audio
R/O	audiowriteformat	format currently being written
R/W	callgroup	call groups for call pickup
R/O	channeltype	technology used for channel
R/W	language	language for sounds played
R/W	musicclass	class (from musiconhold.conf) for hold music
R/W	parkinglot	parkinglot for parking
R/W	rxgain	set rxgain level on channel drivers that support it
R/O	state	state for channel
R/W	tonezone	zone for indications played
R/W	txgain	set txgain level on channel drivers that support it
R/O	videonativeformat	format used natively for video

chan_iax2 provides the following additional options:

Read/write	Item	Description
R/W	osptoken	Get or set the OSP token information for a call
R/O	peerip	Get the peer's ip address
R/O	peername	Get the peer's username

chan_sip provides the following additional options:

Read/write	Item	Description
R/O	peerip	Get the IP address of the peer
R/O	recvip	Get the source IP address of the peer
R/O	from	Get the URI from the From: header
R/O	uri	Get the URI from the Contact: header
R/O	useragent	Get the useragent
R/O	peername	Get the name of the peer
R/O	t38passthrough	1 if T38 is offered or enabled in this channel, otherwise 0
R/O	rtpqos *	Get QOS information about the RTP stream
R/O	rtpdest **	Get remote RTP destination information

*The option rtpqos takes two additional arguments:

 Argument 1:
   audio                 Get data about the audio stream
   video                 Get data about the video stream
   text                  Get data about the text stream
 Argument 2:
   local_ssrc            Local SSRC (stream ID)
   local_lostpackets     Local lost packets
   local_jitter          Local calculated jitter
   local_maxjitter       Local calculated jitter (maximum)
   local_minjitter       Local calculated jitter (minimum)
   local_normdevjitter   Local calculated jitter (normal deviation)
   local_stdevjitter     Local calculated jitter (standard deviation)
   local_count           Number of received packets
   remote_ssrc           Remote SSRC (stream ID)
   remote_lostpackets    Remote lost packets
   remote_jitter         Remote reported jitter
   remote_maxjitter      Remote calculated jitter (maximum)
   remote_minjitter      Remote calculated jitter (minimum)
   remote_normdevjitter  Remote calculated jitter (normal deviation)
   remote_stdevjitter    Remote calculated jitter (standard deviation)
   remote_count          Number of transmitted packets
   rtt                   Round trip time
   maxrtt                Round trip time (maximum)
   minrtt                Round trip time (minimum)
   normdevrtt            Round trip time (normal deviation)
   stdevrtt              Round trip time (standard deviation)
   all                   All statistics (in a form suited to logging, but not for parsing)

See also: Asterisk RTCP

**The option rtpdest takes one additional argument:

 Argument 1:
   audio                 Get audio destination
   video                 Get video destination

Notes

• Those items marked R/W above may be both read and set.
• *CLI> show function CHANNEL
• Additional items may be available from the channel driver providing the channel; see its documentation for details.
• Any item requested that is not available on the current channel will return an empty string.

Return value

Returns the resulting string.

Example

 exten => s,1,Set(foo=${CHANNEL(channeltype)})
 exten => s,1,Set(CHANNEL(callgroup)=g3)

See also

• Asterisk variables
• Asterisk functions

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• Asterisk - documentation of application commands