Create an IAX trunk with the following information
Outbound Caller ID Set this to your voipbuster account name
Maximum channels = 1
Outgoing Dial Rules
Dial Rules
0|.
Outbound Dial Prefix = 0044
Outgoing Settings
Trunk Name = voipbuster
PEER Details
context=from-pstn host=213.61.187.150
insecure=very
notransfer=yes
secret=YOUR-VOIPBUSTER-PASSWORD
type=peer
username=YOUR_VOIPBUSTER-ACCOUNT-NAME
Incoming Settings
leave all of the field’s blank
Registration
Register String = YOUR-PASSWORD:YOUR-ACCOUNT-NAME@voipbuster