[asterisk-dev] Understanding call handling in Asterisk

[varun.rapelly at spectross.com]

Hi,

I am a newbie to Asterisk; need help understanding three-way conferencing & 
call-transfer features implemented over standard extensions i.e. on a 
TDM800P card (4 FXO + 4FXS)

In Asterisk I have observed that if an extension is already participating in 
an active call (e.g. Ext A & Ext B communicating):

1. An incoming call to one of these active extensions would be presented 
with call-wait beeps (e.g. Ext A receives call-wait beeps as Ext C is 
attempting to call Ext A).

2. The call waiting may be answered by pressing Hook-Flash, placing the 
previously active call on hold (e.g. C answered; A & C communicate; B placed 
on hold).

3. The calls could be toggled by subsequent Hook-Flash's (e.g. A & B 
communicate; C placed on hold).

Queries:
1. If the extension which received call-wait beeps hangs-up then the call 
waiting/the call placed on hold returns as a new call. I was expecting the 
call to be transferred (A hangs-up, B & C communicate), how could the call 
be transferred? I expected this feature to be available in Asterisk as this 
is a very normal feature available on any PBX and used extensively in Call 
Transfer.

2. How could the extension that received call-wait beeps initiate a 
three-way conference with the other extensions (A, B & C in three-way 
conference)? I expected this feature to be available in Asterisk as this is 
a very normal feature available on any PBX and used extensively in 3-way 
Call Conference.

Regds.
Varun