ErlBBlocking()

To estimate how many lines are required in a trunk group if the offered traffic is known, use:

=ErlBLines(x,y)

This function takes two parameters:

•	x is the busy hour traffic in Erlangs

•	y is the target blocking figure

For example, to estimate how the lines are required for 100 Erlangs at 0.025 (2.5%) blocking, enter:

=ErlBLines(100,0.025)

The answer should be 111

As with other Excel functions, you can either enter absolute values as the parameters, or you can add references to other cell on the same workbook or other open workbooks.