NEC univerge SV9100 Programming Manual page 95

Issue 4.0
Conditions
The Keep Alive message must be sent and a response not received for the retry count, for the link to

be taken out of service and the calls in progress and Park Hold orbits to be released. For example, if
an ISDN NetLink connection is disconnected at Layer 1, then the Keep Alive message cannot be
sent, therefore the Keep Alive operation will not occur.
Feature Cross Reference
None
SV9100 Programming Manual 2-55