[Asterisk-Users] Feature ver 1/2 Questions

[Clif Jones]

I have setup Asterisk to work with a SIP gateway, some SIP phones
and the Digium FXS/FXO development card combo on another *
box with pretty good results so far.  Here are a couple of questions
that I have that wasn't obvious from the documentation:

Voicemail vs Voicemail2 - What is the major difference between these
and does Voicemail2 use different parameters or config file options?
Voicemail was the only one I found documented.

IAX vs IAX2 - See documentation of IAX and have it working but I
see a few examples floating around using IAX2.  Are there any different
parameters or config file options between the two?  I read that IAX2
has a more efficient payload mechanism but what else can anyone tell
me.

Thanks for the help!