Yealink SIP-T48S User Manual page 165

(Optional.) Enter the no answer forward on code or off code respectively in the
4)
On Code or Off Code field.
Tap the Save soft key to accept the change.
4.
The icon on the idle screen indicates that the call forward is enabled.
To enable call forward in custom mode:
Tap ->Features->Call Forward or press
1.
Tap the desired account.
2.
Tap the desired forwarding type.
3.
Depending on your selection:
4.
If you tap Always Forward:
a)
Tap the On radio box of the Always Forward field.
1)
Enter the destination number you want to forward all incoming calls to in the
2)
Forward to field.
Basic Call Features
when the phone is idle.
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