Asterisk server - How to do paging / intercom / announcements?

http://www.voip-info.org/wiki/view/Asterisk+cmd+Page

I found the following suggestion in another thread, will this work with Asterisk and Grandstream?

From: https://www.experts-exchange.com/questions/24311183/Intercom-Paging-w-Aastra-VOIP-SIP-Handsets-w-Asterisk-Server.html#discussion

darrickhartman:
A few notes on this and then the answer:
 
1).  By default the Aastra phones will autoanswer, even if a call is in progress when you 'page/intercom' to a phone or group of phones.  I usually disable this because it makes no sense to allow this behavior.
 
2). This is pretty easy to accomplish by creating one or more 'ring groups', then calling those groups with a few sip headers added.  Below is the dialplan code you'll need to add.  I usually do this with a macro.
 
[macro-intercom]                                        
; ARG1 - intercom extension                        
exten => s,1,SIPAddHeader(Call-Info:answer-after=0)                                                
exten => s,n,SIPAddHeader(Alert-Info:alert_info=RA)                                  
exten => s,n,Dial(SIP/${ARG1:1}|20)                                    
exten => s,n,Congestion  
 
[intercom]                                    
exten => 7XXX,1,Macro(intercom,${EXTEN})
 
Now if you dial 7101 for example, you'll be able to "intercom" to extension 101
 
If you need to 'page' groups of people, you'll want something like this
 
[paging]                                                    
;page all                                        
exten => 777,1,SIPAddHeader(Call-Info:answer-after=0)
exten => 777,n,SIPAddHeader(Alert-Info:ALERT_INFO=RA)
exten => 777,n,Page(${PAGEOFFICE}&Zap/7|20)      
exten => 777,n,Hangup()    
 
The PAGEOFFICE is set as a global variable that contains a list of the SIP devices to page.
 
PAGEOFFICE=SIP/100&SIP/102&SIP/103&/SIP/104
 
You can then dial 777 (or program a speed dial to be 777) from any phones that include the page context.  You can have any number of these paging groups, just pick a different extension (778, 779...)

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Note
As of Aug 16 2006, the following firmware versions seem to work when using SIPAddHeader(Call-Info: sip:\;answer-after=0) for auto-answer. While using SIPAddHeader(Call-Info: answer-after=0) does work for Grandstream it does not for Aastra or Snom;
   Aastra - 480i - 1.4
   Grandstream - GXP2000 - 1.1.0.16
   Snom - 360 - 6.2.3

I guess I will test this out and report.

You have to keep in mind you're limited to what your phones can do. If the grandstream phones wont support auto-answer, it will never work.

That is the kind of question I should be asking!

From Grandstream:

Does the BudgeTone have the Off hook Auto-Dial and Auto-Answer feature?        
     BudgeTone 100 and BT200 models support both these features.

That's good news.

That came from this link - just in case anyone finds this thread in the future.

http://www.grandstream.com/faqsbudgetone.html#B7

Here's what I found for th BT 200 in the user manual... it looks like it works, though you have to turn on the option on the phone.

-------------------------------------------------------------------------------------------------------------
http://www.grandstream.com/user_manuals/BT200_User_Manual.pdf
Set to Intercom/Paging mode, it will answer the call based on the SIP info header from the server. Allow Auto Answer by Call-InfoIf the Call-Info header contains answer-after=0, the call be answered automatically (so called paging mode).

Thanks for the help.  I meant to try this and post back, but it is taking too long.