System Service Extension Numbers

Reserved System Extension Numbers

PortSIP PBX assigns default extension numbers to built-in system services. These numbers are reserved for system use and cannot be assigned to user extensions.

Default System Extensions

Service	Default Extension	Where to Change It
Call Announcement Service	555	Advanced Services > Automatic Callback
Call Park Service	666	Advanced Services > Call Park > Global Settings
Voicemail Service	777	Advanced > Voicemail
Call Monitor Service	888	Contact Center > Monitor Service

Important Notes

• These extension numbers are reserved by default and are unavailable when creating user extensions.

• If you change a system extension number, make sure the new number does not conflict with any existing user extension, ring group, call queue, IVR, or other system service.

• After changing a system extension number, inform users and administrators who rely on the previous number.