There has been a growing concern, among public safety administrators in various states and other interested parties, about the increasing degree of inconsistency in the use of specific E9-1-1 data fields for varying types of ALI-related data items. While this has provided a degree of customization to support varied PSAP data processes, it also has driven a large set of variations in SCP and MPC programming, and in ALI server data handling, along with expensive customizing of CAD and Mapping system software.

As in other aspects of 9-1-1 data handling, what might be considered a positive situation - a high degree of flexibility - also can carry a high degree of complexity, when the national level view is considered. As a result, a balance between flexibility and complexity usually provides necessary real service capabilities with simplification and overall cost savings, due to lessened complexity.

This Standard is to provide a common format and rules for the submission of wireless maintenance cell data for call routing and ALI display review and approval by the 9-1-1 Governing Authority in existing E9-1-1 Service deployments.

The NENA Wireless Overflow, Default and Diverse routing recommendations document was developed to provide guidance in the routing development associated with wireless Phase I and Phase II deployment efforts. This document provides recommended terminology definitions, describes each call routing scenario, and associated routing recommendations.