T48G Intercom Auto-answer

[jolouis]

Hey CM21,

Let me see if I can help as I know sometimes the Yealink answers are not quite self-explanitory ;o)

Let's start with 2)

2) Correct, there is no difference in what the phone sends to the server (that I have been able to find) between BLF, Speed Dial, or Intercom. They all do the same thing. For your purpose BLF is most likely what you want though as it gives you the most control over the status...

which brings us to

1) With a button type BLF, you get to configure two settings: value, and extension. Value is the thing dialed by the phone to the server. Extension is the hint that the phone uses to update the BLF state. So in your case, you might use:
Value: *80123 (*80 + extension)
Extension: 123
That will cause the phone to monitor 123 and update the BLF state, but when you press the button it will attempt to dial *80123.

Which finally brings us to

3) Asterisk itself does not have some built-in intercom code. If you are running FreePBX or some other GUI that automatically builds your Asterisk dial plan, then that GUI MAY generate an intercom dialplan for you. All this bit of dialplan does is add some SIP headers that tell the phone to try and auto-answer. What headers? Yealink describes them here:
http://support.yealink.com/faq/faqInfo?id=308

If you add any of those 3 headers before making the call out it should work. i.e.

exten => _*80.,1,SIPAddHeader(Alert-Info:answer-after=0)
exten => _*80,n,Set(realNumber=${EXTEN:3})
exten => _*80,n,Dial(${realNumber})

You'd have to add that to a context that was applicable to your existing dialplan and that's way beyond what we are talking about here, but that should give you the idea.

Thanks,

-Rob