Asterisk SIP Trunk with Nortel IPPBX

Asterisk SIP Trunk with Nortel IPPBX
username=0********
usereqphone=yes
type=peer
secret=844******
realm=sip.mmm.net.tw
nat=yes
insecure=very
host=sip.mmm.net.tw
fromuser=0*****
fromdomain=sip.mmm.net.tw
disallow=all
allow=g729