Emergency Service Number (ESN) is used for what purpose?

• A. A code used to transfer funds for emergency services.
• B. An alias for the caller's phone number.
• C. A geographic code for zone.
• D. A number assigned to an emergency service number that is used by the 911 selective router to properly route a 911 call and to associate the English Language Translations of the ALI displays of Law Enforcement, Fire protection and Emergency Medical Service agency names.

Answer: (D)

Emergency Service Number identifies the specific emergency service provider tied to a 911 call and is used by the 911 selective router to route the call to the correct public safety answering point. It also ties into the Automatic Location Identification (ALI) system so that the English-language translations of the agency names for law enforcement, fire, and emergency medical services display correctly to the call-taker. This ensures the right PSAP handles the call and the right agency names appear on screen for responders.

It’s not about transferring funds, it isn’t an alias for the caller’s phone number, and it isn’t a geographic zone code. The ESN’s purpose is routing accuracy and correct agency display within the 911 system.