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Reserved Number Space

The following numbers should not be assigned within a domain because they are reserved for system functions.

Restricted Numbering
00-99Reserved for internal use
411Information
611Customer Service
911Emergency
933Emergency Testing
988National Suicide Hotline
700-799Used for Dynamic Call Parking Queues
900-999Reserved due to 911 system feature
5000/9900Unregistered Login to VMail (prompted for acct no and password)
5002/9902Hot Desking Sign In
7000-7999These are unusable as extension numbers because they conflict with the 7+extension rule to transfer a call directly to voicemail
9900-9999System Features
9999Hot Desk/Hoteling Deactivate

Refer to the following table for assigning users or handling call routing.

Best Practice Dial Plan
100-599User Extensions
800-899User Extensions
1000-4999User Extensions
5003-6999User Extensions
8000-8999User Extensions
9000-9399User Extensions
9400-9899Special Extensions*

Although there is not a set method that must be adhered to for special extensions, we generally recommend the following groups for ease and convenience. This also aids in faster troubleshooting scenarios.

Recommendation for Special Extensions
9401-9499Call Routing Users
9501-9599Auto Attendants
9601-9699Call Queues
9701-9799Conference Bridges
9801-9899Miscellaneous
(Cell Phones, Fax Users, VM Box)

If you have any questions as it relates to the number space within Prysm Voice then please reach out to our support team.

Updated on July 17, 2020

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