TNG has a standard output format.
This output can be used to integrate with any 3rd party software. You will need to get integration software to convert the standard TNG output to what the 3rd party software requires - in this case Opera.
Please see forum post:
TNG Export format: TNG EXPORT FORMAT
If you have TNG, you have access to the call details. You do not require any additional licensing on the TNG side to access the call details for 3rd Party Integration.
As long as TNG is receiving call details it will be available as per 2 options explained in above link. Note that TNG has the feature to alert you if no calls has been received for a configured period within your office hours, please refer to forum post: TNG Alarm Configuration (TNG v1.0.6.5 or newer)
PLEASE NOTE: Datatex does not provide the integration software. We only provide the TNG call details in a format so that your 3rd party integration support can process the required details to Opera. The integration side must contact Opera as to what is required and if for example licensing is required.