NEC DSX Feature Handbook page 58

Features
58 | DSX |
All Call
Forward
Exit
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Using the CLEAR Key (Super Display)
Cancel all Call Forwarding system-wide (access levels 4 and 5 only).
Simultaneously cancel all the Call Forwarding system-wide.
Yes
Back up to the previous level without canceling all the Call Forwarding
Cancel
system-wide..
Exit to the idle menu display.
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