Topology:
PSTN E1 -> Asterisk -> IAX TRUNK VIA INTERNET -> ASTERISK -> H323 Gatekeeper/gateway

---extensions.conf ---
[general]
writeprotect=no

[globals]
CONSOLE=Console/dsp

[default]
exten => _XXXXXXXXXXXXXX,1,Dial(IAX2/IAX_GATE)




---iax.conf---
[general]
bandwidth=low
trunkfreq=20

[iax_gate]
type=peer
host=192.168.3.200
context=*
qualify=yes
trunk=yes