CHANNEL()

`CHANNEL()`
	Appendix C. Functions in the dialplan

`CHANNEL()`

CHANNEL(field)

(beginning Asterisk 1.4)

Reads/sets specific channel parameters. The field is one of the following (only reading is possible unless otherwise noted):

audioreadformat: The format for incoming audio on the channel
audionativeformat: The native audio format of the channel
audiowriteformat: The format for outgoing audio on the channel
callgroup: Extensions in Asterisk can be sorted into call groups numbered from 0 - 63, e.g. as a client number.^[72]
channeltype: The channel driver, or "technology" of the current channel, e.g.: IAX or SIP
language: The language for voice prompts. May be set as well as read
musicclass: The music-on-hold class, as defined in musiconhold.conf. May be set as well as read
state: State of the channel (Down, Rsrvd, OffHook, Dialing, Ring, Ringing, Up, Busy, Dialing Offhook, Pre-ring, Unknown)
tonezone: The "tone zone" defines the standard tone indications (dialing, ringing, busy, etc.) for specific regions and countries. This is set in the configuration file for the channel driver (e.g. zaptel.conf) with the parameters loadzone and defaultzone. Possible values are (as defined in indications.conf): at, au, be, br, ch, cl, cn, cz, de, dk, ee, es, fi, fr, gr, hu, it, lt, mx, ml, no, nz, pl, pt, ru, se, sg, uk, us, us-old, tw, ve, za.
videonativeformat: The native video format of the channel

In addition to the field described above, specific channel drivers can make others available. To learn more about these, look in the documentation for the specific channel driver. Fields which are unavailable on the current channel will return an empty string.

; Query the channel type:
exten => 123,1,Set(foo=${CHANNEL(channeltype)})

; Change language to English:
exten => 123,1,Set(CHANNEL(language)=en)


Internal help for this application in Asterisk 1.4: -= Info about function 'CHANNEL' =- [Syntax] CHANNEL(item) [Synopsis] Gets/sets various pieces of information about the channel. [Description] Gets/set various pieces of information about the channel. Standard items (provided by all channel technologies) are: 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 rxgain set rxgain level on channel drivers that suppor t it R/O state state for channel R/W tonezone zone for indications played R/W txgain set txgain level on channel drivers that suppor t it R/O videonativeformat format used natively for video 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. diff output to internal help in Asterisk 1.2: -- not available in Version 1.2 --

Internal help for this application in Asterisk 1.4:

  -= Info about function 'CHANNEL' =- 

[Syntax]
CHANNEL(item)

[Synopsis]
Gets/sets various pieces of information about the channel.

[Description]
Gets/set various pieces of information about the channel.
Standard items (provided by all channel technologies) are:
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  rxgain              set rxgain level on channel drivers that suppor
t it
R/O  state               state for channel
R/W  tonezone            zone for indications played
R/W  txgain              set txgain level on channel drivers that suppor
t it
R/O  videonativeformat   format used natively for video

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.

diff output to internal help in Asterisk 1.2:

-- not available in Version 1.2 --

^[72]This limit of 64 call groups appears to be completely arbitrary and may not be sufficient for all users.


`CDR()`	\|	`CHECKSIPDOMAIN()`

CHANNEL()

WARNING: ALPHA-VERSION!

`CHANNEL()`