asterisk auto dialing using call file

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asterisk auto dialing using call file

Asterisk call files are structured files which, when moved to the appropriate directory, are able to automatically place calls using Asterisk.

Call files are a great way place calls automatically without using more complex Asterisk features like the AGI, AMI, and dialplan, and require very little technical knowledge to use.
Call files are like a shell script for Asterisk. A user or application writes a call file into /var/spool/asterisk/outgoing/ where Asterisk processes it immediately

Asterisk has the ability to initiate a call from outside of the normal methods such as the dialplan, manager interface, or spooling interface.

Using the call file method, you must give Asterisk the following information:

  • How to perform the call, similar to the Dial() application
  • What to do when the call is answered

Call File Syntax

The call file consists of <Key>: <value> pairs; one per line.

Comments are indicated by a ‘#’ character that begins a line, or follows a space or tab character. To be consistent with the configuration files in Asterisk, comments can also be indicated by a semicolon. However, the multiline comments (;—-;) used in Asterisk configuration files are not supported. Semicolons can be escaped by a backslash.

The following keys-value pairs are used to specify how setup a call:

  • Channel: <channel> – The channel to use for the new call, in the form technology/resource as in the Dial application. This value is required.
  • Callerid: <callerid> – The caller id to use.
  • WaitTime: <number> – How many seconds to wait for an answer before the call fails (ring cycle). Defaults to 45 seconds.
  • MaxRetries: <number> – Number of retries before failing, not including the initial attempt. Default = 0 e.g. don’t retry if fails.
  • RetryTime: <number> – How many seconds to wait before retry. The default is 300 (5 minutes).
  • Account: <account> – The account code for the call. This value will be assigned to CDR(accountcode)

When the call answers there are two choices:

  1. Execute a single application, or
  2. Execute the dialplan at the specified context/extension/priority.

Let us have an complete example:

Dialplan setting to process auto dialing

[voicebroadcast]
exten => 777,1,Answer()
exten => 777,n,Wait(1)
exten => 777,n,Playback(hello-world)
exten => 777,n,Wait(1)
exten => 777,n,Hangup()

We will create a call file called broadcast.call in /tmp/ with the following content:
vi /tmp/broadcast.call
save the file
Channel: SIP/1000
MaxRetries: 2
RetryTime: 60
WaitTime: 30
Context: voicebroadcast
Extension: 777

Now we move this file with mv /tmp/broadcast.call /var/spool/asterisk/outgoing/

Understanding asterisk call file

The following happens:
  • Asterisk polls the /var/spool/asterisk/outgoing/ for new call files and processes any it finds.
  • Asterisk opens a connection to device SIP/1000. If the device is in use or not answered, Asterisk tries two more times (seeMaxRetries).
  • If someone answers SIP/1000, Asterisk begins processing extension 777 in the context [voicebroadcast]. In this case, Asterisk plays hello-world to the answering party.

Parameters used in call file

Parameters

Name Explanation/Notes
Channel: <channel> The channel upon which to initiate the call
Callerid: <id> The caller ID to be used for the call.
WaitTime: <seconds> Number of seconds the system waits for the call to be answered. If not specified, defaults to 45 seconds.
MaxRetries: <integer> Maximum number of dial retries (if an attempt fails because the device is busy or not reachable). If not specified, defaults to 0 (only one attempt is made).
RetryTime: <seconds> Number of seconds to wait until the next dial attempt. If not specified, defaults to 300 seconds.
Account: <account> The account code for the CDR.
Context: <context> The destination context.
Extension: <exten> The destination extension, in which dialplan execution begins if the device is answered.
Priority: <priority> The destination priority. If not specified, defaults to 1.
Setvar: <var=value> lets you set one or more channel variables
Archive: <yes|no> By default, call files are deleted immediately upon execution. If Archive: yes is set, they are copied into /var/spool/asterisk/outgoing_done/ instead. Asterisk adds a line to the call file which describes the result:Status: <Expired|Completed|Failed>

 

Issue with Call file

 

For any query or issue, feel free to discuss on http://discuss.eduguru.in
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