[asterisk-users] Doorphone vs. Grandstream BT101

[Jay Milk]

I've done all the googling I can on this, and have come to the 
conclusion that a Grandstream BT101 can be abused to be a door phone.  
Could someone with access to one, confirm that the following is possible?

Researched:
1. When set to auto-answer, dialing the phone will result in a short 
beep and instant speaker-phone connection.
2. When pressing the "message" button while on-hook, the phone will 
activate speaker-phone and dial the number configured for voice mail 
retrieval.

Assumptions:
3. Pressing the "message" button additional times will simply be ignored 
by the phone.
4. Hanging up the other end of the call will deactivate the speaker 
phone and cause the phone to go on-hook. (This is the behavior I see on 
a Polycom 430).

If the researched functions and my assumptions are correct, this phone 
would make an ideal door-phone;  The message button becomes the 
call-button, which rings every phone in the house until answered (for 
intercom).  It could even take messages.  Listen-in on the door works 
through the auto-answer feature.

Could someone confirm this for me?

Thanks!