With Asterisk SIP trunks you must give the trunk a name on the
Asterisk side, else TNG will see it as a internal call.
For the Asterisk version on the TNG software, trunk values needs
to be an IP address or start with "trunk_", for example: trunk_telkom1,
to qualify as a trunk. Once this is configured, TNG will see
it as a trunk and work correctly.
If trunk column on the Call List page list the trunk as
VOIP-INT
INTERNAL
VOIP-EXT
it will not cost, because it is an internal call.
ALSO SEE:
Why is my internal calls being costed
TNG Costing of calls.