ESN
1. Emergency Service Number A three-digit number that is assigned to the caller's telephone number in the tandem office translations. The emergency...
Definition:
Emergency Service Messaging Interface. Emergency Information Services Interface (EISI) and Emergency Service
Messaging Interface (ESMI) comprise a suite of standards under the umbrella of Emergency Services Network Interfaces
(ESNI) that enable an evolutionary migration from existing PSAP ALI services and interfaces to next generation services.