Start VoIP Calculator by choosing VoIP Calculator | VoIP Calculator from the Start Menu. Use the Tab Control near the top of the window to select the Erlangs and IP Bandwidth Calculator.
If you were using this calculator last time you closed the VoIP Calculator, then you will automatically be returned to this calculator.
See also
Introduction to the Erlangs and IP Bandwidth Calculator
The Erlangs and IP Bandwidth Calculator layout