The Care and Feeding of ISDN4BSD
6.1.3 The Entry Configuration	6.1 The isdnd.rc Configuration	6.1.5 Configuring Simple Mode

6.1.4 Idletime Calculation for Incoming Calls

It is assumed that the calling side knows most about charging structures and such and as a consequence only the keyword idletime-incoming has a function for incoming calls.

For incoming calls the line is constantly monitored and in case there was no traffic taking place for the time in seconds specified by idletime-incoming, the call is closed.

Typically, idletime-incoming is used as a last resort and is therefore set much higher than a charging unit time: typical values are one to five minutes.