Integrated Services Access Page 765 of 1814International ISDN PRI Feature description and administrationThe sum of all Min values for the service route cannot exceed the number ofB-channels defined for the ISA master route.When the NSF prompt is YES and the Max value is reached in a service route,the All Trunks Busy (ATB) counter is incremented. The ATB count is notincremented when NSF is NO.The ATB value is provided during the printing of traffic reports. The ATB ispegged against individual service routes when the maximum number ofB-channels reserved for that call type has been reached. The ATB counter ofan ISA master route is also incremented when the last B-channel of the ISAmaster route is busied. This occurs whether the NSF prompt is YES or NO.Service IdentifierIn addition to the call type (route type), each call is identified by a serviceIdentifier (SID), which is used by the Meridian 1 and the central office forrouting. The SID prompt is available when the NSF prompt is set to YES.These service identifiers must be set up in coordination with the central officefor call type delivery and routing purposes.The Service Identifier allows a call type with multiple SIDs such as INWATSto go to prespecified Directory Numbers.Before this feature, the SID defaults to the route number, and the value rangewas 0–127. With the introduction of this feature, the SID no longer has adefault value. Also, the value range of SIDs is expanded to support 0–511.ISA capabilityBasic ISA functionality includes the following:• Incoming Digit Conversion (IDC) is supported for DID call type only.• All INWATS calls terminate to the attendant console.• ISA supports two-way DID trunk types (as do all PRI connections to acentral office).• A total of 127 SID routes is allowed for all trunk types per customer.• Multiple routes can be defined.• Calls are routed based on Service Identifier (SID) value.
