On the TNG Home page, select the 'Call Cost Calculator' icon from the icons in the centre of the screen.
On the Call Cost Calculator page, select:
date and time of call to cost
enter the telephone number as you would dial it.
enter the duration of the call.
You can specify the ratebook or leave it on ALL to compare the different ratebooks.
See screenshot:
NOTE: to have access to the attachment, you need to be registered and logged in.