$ more /etc/asterisk/h323.conf
[general]
port = 1720
disallow=all
allow=g729
allow=gsm
gatekeeper = DISABLE

[48012000]
type=friend
e164=48012000
context=default
[48012001]
type=friend
e164=48012001
context=default
--------------------------
> bt full
#0  OpalMediaFormat::GetPayloadType (this=0x8) at /usr/local/src/openh323/include/mediafmt.h:157
        this = (OpalMediaFormat *) 0x8
#1  0x40555130 in MyH323_ExternalRTPChannel::Start (this=0x81837c8) at ast_h323.cpp:931
        this = (MyH323_ExternalRTPChannel *) 0x81837c8
        mediaFormat = (OpalMediaFormat &) @0x8: Cannot access memory at address 0x8