For IP Office Basic Edition 6.1 and higher, extension users are created in the system configuration for all possible users regardless of whether they are matched by installed extension ports. Those user extensions without a physical port are referred to as 'phantom' extensions.

The main purpose of phantom extensions is to provide voicemail mailboxes that are not associated with an existing physical extension. These mailboxes can be accessed and used by the auto attendant menus and other functions.

The system assumes that the base control unit is always fully populated with up to 24 extensions, either real or phantom or a mix, to which it assigns extension numbers in sequence. It does this before assigning extension numbers to any real extensions on attached external expansion modules up to the system extension limit. If the system extension limit has not been exceeded, any remaining extension numbers are assigned to additional phantom extensions.

 

The system web management menus allow selection of a phantom user extension number in the same was as for normal physical extension numbers. That includes using a phantom extension as the destination in an auto attendant, trunk DID call map, SIP call by call mapping, etc.

Calls to a phantom extensions are treated as follows:

Calls go immediately to the phantom user's voicemail mailbox. Forwarded or transferred calls go to the mailbox of the user doing the transfer or forward.

If the phantom extension is included in a hunt group, they are ignored.

Callers can use the phantom user's mailbox DTMF breakout settings, if configured, to be transferred to another destination.

Calls can be transferred to a phantom extension. Since the calls go immediately to voicemail, no transfer return is supported.

Joining or bridging to a call that has been sent to a phantom extension’s mailbox will drop the phantom extension from the call in the same way it does for a physical extension.

Calls to a phantom extension cannot be picked up.

The phantom extensions are supported within the auto attendant actions Dial by Name, Dial by Number and Transfer to Number.

Mailbox access for message collection and mailbox configuration is achieved by dialing 778 from any telephone, then entering the phantom extension number and the mailbox access code if it has already been configured. Mailboxes with a configured access code can also be accessed by external calls.

Phantom extensions can be used as the line coverage extension for a line. In this case, the phantom extension's VMS Coverage Rings setting is used before the call goes to the phantom user's mailbox.  

Auto Dial Intercom buttons can be set to route calls to a phantom extension.

When using system web management, when selecting extensions in the various menus, a phantom extension is indicated by a # character. The extensions Equipment Type is fixed as Phantom.

The phantom extension's Automatic VMS Coverage setting can be used to disable mailbox operation. If this is done, calls to the phantom extension will hear busy tone.

 

The following features are specifically are not supported using phantom extensions:

A phantom extension cannot be configured as any other extension type, ie. loudspeaker, door phone, fax machine or standard extension.

A phantom extension cannot be configured as a night service alert extension.

A phantom extension cannot be configured as a hotline extension.

A phantom extension cannot be added to a hunt group, pickup group or calling group.

A phantom extension specified as the destination for call forwarding or follow me is ignored. Instead calls will continue to alert at the forwarded user.

A phantom extension specified as the destination for another extension's call coverage is ignored. Instead calls will continue to alert at the covered extension.