DIVA T/A ISDN Modem User’s Guide ◆ Page 137
Billing Interval ExampleSuppose a user is charged a flat fee of $.08 each time a connection is established, plus $.01
per minute of B-channel usage.
Since the flat fee of $.08 is quite high relative to the per minute charge of $.01, the user
should be careful not disconnect and reconnect too often. A good solution would be to set
the initial billing interval to 480 (8 minutes), and the billing interval to 60 (1 minute).
With these settings, the minimum time the second B-channel remains connected is 8
minutes (as spe cified by the initial billing interval). If the second B-channel is needed longer
than 8 minutes, the extra connection time will always occur in increments of 1 minute (as
specified by the billing interval), e.g. for a total time of 9 minutes, 10 minutes, 11 minutes etc.
How the interval settings effect costs can best be seen with a usage scenario. Take a sample
time period of 10 minutes in which the second B-channel is first needed for 2 minutes, is not
needed for the next 5 minutes, and is then needed for another 2.5 minutes. Compare the
costs when the initial billing interval is set to 240 and 480, as shown below.
Initial Billing Interval = 24 0 (4 minutes )
In this case the second B-chann el would need to connect twice (since it is dropped after 4
minutes). The total cost would be:
Initial Billing Interval = 48 0 (8 minutes )
The second B-channel would only need to connec t once (since the first connection is not
dropped). The total cost would be:
Note that there is no ‘one’ solution for setting the parameters, the key is to find a balance
between the variables.
Connection cost $.08 x 2 connections = $.16
Call # 1 $.01 x 4 minutes = $.04
Call # 2 $.01 x 4 minute = $.04
Total = $.24
Connection cost $.08 x 1 connections = $.08
Call $.01 x 10 minutes = $.10
Total = $.18