Extension Numbering & Reserved Numbers

Overview

📜 Scope

Outlines the available numbers for extensions and reserved numbers.

✔️ Requirements

🔗 Links

Extension Range	Designated Purpose
0 - 99	Reserved for internal use
211	FCC standard for community support information (free and confidential services) in some regions of the United States
311	FCC standard for municipal government services (non-emergency line) in some regions of the United States
411	Local Directory Assistance
511	FCC standard to access traveler information services in some regions of Canada and the United States
611	Customer Service
711	FCC requirement to connect a deaf caller to a Telephone Relay Service
811	Call Before You Dig
911	Emergency Services
933	Emergency Testing
988	National Suicide Hotline
700 - 719	Call Parking without Ringback
720 - 799	Call Parking with Ringback
900 - 999	Reserved for Emergency, Municipal, Community and Other Services
5000	Unregistered Login to Voicemail - Prompts for extension and password
5001	Registered Login to Voicemail - Prompts for password only
9900	Unregistered Login to Voicemail - Prompts for extension and password
9901	Registered Login to Voicemail - Prompts for password only
9902	Hot Desking Sign In
7000 - 7999	Transfer to Voicemail
9900 - 9999	Reserved for System Features
70000 - 79999	Transfer to Voicemail

3 Digit Exensions

4 Digit Extensions

Extension Range	Usage
700 - 719	Call Parks - No Ringback
720 - 799	Call Parks - Ringback
9000 - 9099	Auto Attendants
9100 - 9199	Call Queues (Excluding Call Parks)
9200 - 9299	Routing Extensions
9300 - 9399	Virtual Users
9400 - 9499	Non-User Voicemails
9500 - 9599	Fax Users
9600 - 9699	External Forwarding Extensions
9700 - 9799	Special Extensions
9800 - 9999	System Reserved