Sayson IP Phone Auto Answer

How To Configure Asterisk Auto Answer with Aastra IP Phones

The ALERT_INFO variable works for 480i, 480i CT, 9133i, 9112i firmware 1.2.x or later

Set it like in the example below:

Asterisk 1.4.x and higher:
exten=_*55XXX,1,SIPAddHeader(Alert-Info: info=alert-autoanswer)

Asterisk 1.2.x:

(*55 will be the prefix for the normal phone number; if a single digit is used --or anything of a different length-- adjust the slicing of the ${EXTEN}, like ${EXTEN:1} for a single digit)

Note: It's possible to make Sayson analog ADSI phones AutoAnswer as well. This has been done on other PBX systems. The trick is to create an ADSI script that will go off-hook when a certain sequence of events occur like caller-id followed by message waiting. For more information, email

January 30 2007
by KMorley

The following recipe works for Asterisk 1.2.13, FreePBX 2.2.0 and Aastra 480i firmware

There are at least two ways to get the intercom splash tone to work using the stock extensions_additional.conf file auto-generated by FreePBX. The low-tech way is to modify the DIAL statement to play a sound file (beep.gsm in this example):

exten => _*80.,n,Dial(Local/${dialnumber}@from-internal/n,12,TtrA(beep))

My preference is to send a SIP packet to the phone requesting that the phone internally generate the splash tone. This method avoids the timing problems listed in the methods below. Simply replace:

exten => _*80.,n,Set(__ALERT_INFO=Ring Answer)


exten => _*80.,n,Set(__SIPADDHEADER=Alert-Info: \;info=alert-autoanswer)
(two underscores preceed SIPADDHEADER)

Note that FreePBX will overwrite these modifications the next time it auto-generates extensions_additional.conf unless you modify the FreePBX module that actually does the auto-generation.

My aastra.cfg file contains the following intercom-related settings:

sip intercom type: 2
sip intercom line: 1
sip intercom prefix code: *80
sip intercom mute mic: 0
sip allow auto answer: 1

Regardless of documentation, the following settings don't seem to have any impact on intercom functionality:

directed pickup: 1
play a ring splash: 1
priority alerting enabled: 1

Note that the SetVar methods listed below did not work for my combination of Asterisk/FreePBX/AAstra 480i firmware. Further, I've read that the SetVar method is or will be deprecated in future versions of Asterisk. Also, there may be other Alert-Info messages that these phones will respond to, but *none* are publicly documented. I discovered this alert strictly through trial and error.
EDIT: why not simply do a "strings" on the firmware binary of the phone to check for possibly supported commands?
Why go for the easy way when there is a much more challenging way? ;-)

by Mustardman
Tested with Asterisk 1.2 and Aastra v1.4 firmware. Added _ in front of ALERT_INFO as pointed out by Robert. No longer a delay problem and confirmed that my 9133i beeps on it's own. Both must have been fixed in the newer firmware.
EXTEN:3 matches the number of digits in the extension. Can also use XXX for 3 digits as others have show. I prefer the wildcard "."


by Robertm1771

The following worked for me note the _ is needed at the start of ALERT_INFO to work with CVS-HEAD
XXX matches your phones extension number. I might be mistaken but I think my 480i beeps on pickup.
Using Firmware


by Mustardman
use wildcard "."instead of "X". Add beep to announce autoanswer to called party.

Note: it takes approximately 500ms for phone to produce sound so an audio file with 500ms of silence at the beginning is preferred.

See Also:

Created by: frisketdog, Last modification: Thu 04 of Nov, 2010 (14:37) by admin
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