ShoreTel 530 User Manual page 18

When you put a call that has come in to the monitored extension on hold, the
call is parked on the owner's phone, so that either of you may pick up the call
again.
If your phone is being monitored, the call appears on your phone as if you had
put it on hold yourself, as follows:
The call will stay on the owner's phone for the length of time specified by the
system administrator for Park Timeout before ringing back to your phone.
(The administrator can change this default timeout in Director's Call Control
Options page.)
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