Your IP 335 can be set to forward calls with the following precedure:
Press Menu, select Option 1 “Features” with the check mark, then select Option 3 “Forward”.
Scroll and select with the arrow button the forward condition (always, no answer or busy). You will then see “contact”. If there is no number, or you want to change the existing number, then press the check mark to enter or edit the number. Press “ok” when finished.
Now press the down arrow where “disabled” is highlighted, and press the check mark.
Press the forward arrow to switch from Disabled to Enabled, then press ok.
Press the back arrow to get to the save screen and press “Yes”. The phone will now show “call forward enabled” on the idle screen.
To undo call forwarding, go through the same sequence as above, and toggle enabled to disabled, then save the setting by pressing the back arrow key and “Yes”."