AT&T MERLIN LEGEND System Reference Manual page 229

Features
Transfer
Voice/Announce to Busy
System Programming
2-180 Forward and Follow Me
When calls are forwarded to an extension number, a call received on an
Intercom or System Access button rings once at the forwarding station's
Intercom or System Access button (including all assigned Shared System
Access buttons even though a call received on these buttons is not forwarded)
and also rings at the destination station's Intercom or System Access button
(including all assigned Shared System Access buttons).
Inside and outside calls transferred by another user or by a system operator are
forwarded. If a user transfers a call to an extension with calls forwarded, the
extension receiving the forwarded calls hears one burst of ring indicating an
If the extension is a display telephone, the call information appears
inside call.
as an internal call and not an outside call.
Voice-announced calls are not forwarded.
Allow or remove individual extension capability of forwarding calls to an
outside telephone number (Remote Call Forward).
Extensions -> More -> Remote Frwd
Assign or remove principal user of a personal line-specifies that an
individual extension can forward calls received on a specific personal line to
an outside telephone number; calls received on the personal line follow only
the individual extension's Coverage patterns and not the Coverage patterns
of other users who share the line.
LinesTrunks -> More -> PrncipalUsr