[asterisk-users] Is this possible?

[shadowym]

Anyone tried this,

I put in an Asterisk/FreePBX phone system to replace one of those el cheapo
Bizfon analog key systems.  The Bizfon was able to do follow me to analog
lines but I do not believe the capability is in Asterisk.  Of course now it
becomes the one feature they cannot do without.  Somehow the Bizfon is able
to detect if an analog line is answered (without answer supervision).  If
not it goes to the Bizfon voicemail.  I have not figured out a way to do
this in Asterisk/FreePBX.

Anyone know how Bizfon does it? Is there a way to do it in Asterisk?  The
analog lines are standard loop start lines in a hunt group provided by Bell
Canada.  They do not have any type of answer supervision such as polarity
reversal.  I think maybe the Bizfon asks for button press confirmation on
the other end and if not it times out.  That's just a theory though.  With
Asterisk, as soon as an analog line goes off hook and starts ringing
Asterisk set's that line to "answer" state unless it has polarity reversal
(answer supervision for loop start lines).  Once Asterisk thinks the Analog
line is answered you cannot do anything further.  

callprogress=yes provides the functionality I believe but this is a
production environment and that feature does not work reliably enough.  Is
this how bizfon does it maybe?  Maybe they can detect the ringing indicating
the call was not answered?