17.67. SIRI - Single ring burst 
Feature:
Calls incoming over digital central office trunks from other branches via VPN ring
as an
internal call & calls incoming from other sources ring as an external call.
Function:
For incoming calls passing the VPN.
Parameter set: All calls from other branches ring internal (single ring burst).
Parameter not set: All calls from other branches ring external.
AMO-Interrelationships:
It must only be set for the trunks that are used by incoming calls passing the VPN.
Device type:
Only trunks for incoming voice calls.