is a brief introduction to the calculator. For more detailed information, press the Help
Button. For a running record of the results calculated, press the Results button.
Both these functions open new browser windows on your desktop.
- If you know the number of sources and two of the other figures, you can work out the
fourth as follows:
- Enter the number of traffic sources in the Sources box.
- Click on the Unknown radio button representing the unknown variable.
- Enter the 2 other known figures into their edit boxes.
- Press Calc and the result will be calculated and displayed in the remaining edit
- For example, imagine that you have 100 telephone extensions on a PBX, generating 35
Erlangs of traffic during the busy hour and that this traffic is offered to a PSTN link
used solely for that outbound traffic. To calculate how many lines are required in
that trunk group if 2% blocking is acceptable:
- Enter 100 in the Sources box.
- Press the Lines Unknown radio button (this is selected by default).
- Enter 35 in the BHT edit box.
- Enter 0.02 in the Blocking edit box.
- When you press the Calc button, 43 will be displayed in the Lines edit box
indicating that 43 lines would be required in this trunk group. By contrast, the Erlang B Calculator, which does not take the number
of sources into account, would report that 45 lines are required.