TR NWT 000505 : ISSUE 3 REV 4

5.1 General
5.1.1 Organization of this Document
5.2 Call Treatments
5.2.1 Origination Treatment
5.2.1.1 Seizure
5.2.1.2 Power Cross Protection
5.2.1.3 Start
5.2.1.4 Code Registration
5.2.2 Termination Treatment
5.2.2.1 Terminations to Lines
5.2.2.2 Terminations to Trunks
5.2.2.3 Termination of Calls that Cannot be Completed
5.2.2.4 Terminations to Tones and Announcements
5.2.3 Release Treatment
5.2.4 Interruption Treatment
5.2.4.1 Operator Recall
5.2.4.2 Ringback
5.3 Internal Call Processing Functions
5.3.1 Connections
5.3.1.1 Types of Connections
5.3.1.2 Verification of Connections
5.3.2 Class of Service
5.3.2.1 Customer Classes of Service
5.3.2.2 Trunk Classes of Service
5.3.3 Code Interpretation
5.3.3.1 Customer-Dialed Codes
5.3.3.2 Intersystem Incoming Call Destination Codes
5.3.3.3 Operator Services Feature Interactions
5.3.4 Screening
5.3.5 Routing
5.3.5.1 Locally Terminated Calls
5.3.5.2 Outgoing Calls
5.3.5.3 Calls to Invalid Codes
5.3.5.4 Route Transfer
5.3.5.5 Corridor Calls
5.3.6 Outpulsing Code Formulation
5.3.7 Trunk Selection (Hunting)
5.3.7.1 Selecting a Trunk Group
5.3.7.2 Start of Trunk Selection
5.3.7.3 Trunk Selection Goals
5.3.7.4 Trunk Selection Strategy
5.3.7.5 Interoffice Signaling
5.3.8 Internal Overload Control
5.3.8.1 Introduction
5.3.8.2 Indicators, Measurements, and Thresholds
5.3.8.3 Classes of Overload
5.3.8.4 Strategies
5.3.9 Essential Service Protection
5.3.9.1 ESP Implementation Strategies
5.3.10 Automatic Message Accounting (AMA)
5.4 Acronyms
5.5 References
LIST OF FIGURES
Figure 5-1 Call Processing Flowchart for Line Origination
Figure 5-2 Flowchart for Origination Tests
Figure 5-3 Flowchart for Dialing
Figure 5-4 Flowchart for Termination Tests
Figure 5-5 Flowchart for Transmission Path Connection
Figure 5-6 Flowchart for Transmission Path Disconnection
Figure 5-7 Customer Reaction to Delayed Tone
Figure 5-8 Successful versus First-Offered Calls Relative
              to Peak Capacity
LIST OF TABLES
Table 5-1 Operator Services Feature Interactions (Sheet 1 of 4)

Describes Bellcore's view of generic call processing requirements and objectives applicable to basic telephone service. Call Processing is divided into two major parts; Call Treatments: the system actions and responses directly associated with customer line and intersystem facility interface; and Internal Call Processing Functions: the supporting internal system actions necessary to provide proper call treatment.