Usage of the  Alert-Info  header

The SIP Alert-Info header must look like this:

Alert-Info: <http://www.notused.com>;info=alert-event;x-line-id=0

where

• <http://www.notused.com>  -> a dummy URL is required otherwise the specified file (wav format) will be downloaded
• info=alert-group -> the alert-event: a freely defined string configured in any of the following
  • "Alert Internal Text"
  • "Alert External Text"
  • "Alert Group Text"
  • "Internal Ringer Text 0" (1)(2)(3)(4)(5)(6)(7)(8)(9)(10)
  • "Inactive Stream Alert Info Text"
  • e.g.  "Alert Internal Text": internal_calls  ->  info=internal_calls
• x-line-id=0  -> part of the syntax -> not used, will be ignored

exten => s,n,SIPAddHeader("Alert-Info:<http://www.notused.com>\;info=alert-external\;x-line-id=0")

Since this is a security issue as well, additionally the following setting must be switched "on" on the receiving phone:

´Answer After´ Policy / Intercom Policy

You can also use the Alert-Info headers to choose a certain ringtone from the ones available on the phone or reachable to the phone over http (custom melodies). Here is an example of a call that should ring using Ringer 3:

Alert-Info: <http://127.0.0.1/Ringer3>

Here is an example of a call that would ring using an example custom melody from  http://downloads.snom.com/documentation/melody2.wav

Alert-Info: <http://downloads.snom.com/documentation/melody2.wav>