AT&T MERLIN LEGEND System Reference Manual page 459

System Applications
Privacy
Transfer
System Programming
Hardware Requirements
Privacy must be programmed for each station jack that has an Attendant
connected to it.
VMI ports can transfer an incoming call to an outgoing line/trunk.
If a caller incorrectly specifies the answering VMI port as the desired transfer
destination station, the VMI port can inadvertently park the call.
Designate inside dial tone to be the same as the outside line/trunk dial tone.
Assign all Attendants to a calling group and set the group type to "VMI
Generic."
Designate a transfer redirect extension, such as the system operator, to
receive calls that were originally transferred to unanswered or busy
extensions, or to receive calls when a caller fails to respond to the message.
Program all calling groups as "auto-logout." (Auto-logout is the default.)
Program Privacy for each station jack used to connect an Attendant.
012 basic telephone module
MERLIN Attendant unit and cords
MERLIN Attendant 3-27