Reserved Number Space

This article shows all reserved number space

The following numbers should not be assigned within a domain because they are reserved for system functions. If you wish to use extension numbers in the reserved space, Monster will charge $95 per domain for custom programming.


Number Space Purpose
411 Information
611 Customer Service
911 Emergency
933 911 Test Number
700-799 Used for Dynamic Call Parking Queues
99 + Users Extension (Ex. 99 + 100) Reserved to work with Intercom features.
5000 Unregistered Login to VMail (prompted for acct no and password)
5001 Registered Login to VMail (prompted for password only)
5002 Hot Desking Sign In
5003 Requests the User's PIN then provides a 2nd dialtone (useful for calling from phones in public spaces
5004 Reserved for Future Hot Desking Development.
8888 This User has a limited view in the PBX portal. When assigned the Office manager role, the 8888 User can only view the Home and Call History pages. Other Office manager functions are hidden.


NOTE: Extensions should not begin with the number 0, and please use 3 and 4 digit extensions. 2 digit extensions will cause setup issues.