Installation and Administration Guide 33September 2001 Remote Office 9150 descriptionIf the connection is defined as demand, then you can configure minimum callduration and idle timers on the RLC to help reduce call charges.Minimum call duration timerMost ISDN tariffs specify a minimum length of time for which you are chargedwhen you open the line, regardless of the call duration. This is the same as theminimum call charges listed on long distance telephone bills.The minimum call duration timer is used in circuit-switched mode only andspecifies the minimum length of time that each circuit-switched call to the hostPBX remains active, regardless of telephone activity or inactivity. The timershould be configured on the RLC to drop inactive connections just before anadditional charge period is incurred. For example, if the timer is set to 59seconds and your call lasts only 20 seconds, the ISDN connection drops whenthe timer reaches 59 seconds.If another call is made to the host PBX before the timer expires, the timer isreset. The timer tracks the current call.Idle timerThe idle timer identifies the maximum length of time during which an ISDNconnection remains idle before it closes. Idle means that a voice connectionexists but is not active, and buttons are not being pressed on digital telephones.For example, if the idle timer is set on the RLC to 60 seconds, the ISDN callremains open for 60 seconds after you hang up. If you or someone else dialsanother number before 60 seconds have passed, another ISDN connection is notopened.How the timers work to control ISDN costsThe minimum call duration and idle timers work together to control ISDNcharges. The following examples describe what happens when the minimum callduration timer is set to 59 seconds and the idle timer is set to 60 seconds.
