Press the key. The LED lights up. 

Select and confirm. 

Enter the code. 

Press the key. If the key is already in use, its assignment appears on the screen. 

Confirm. 

Select and confirm the function, such as "Do not disturb".
All programmable functions appear on the screen. See Quick-Reference Operating Instructions (Appendix): section ... about function keys. 

Select and confirm.
Some functions (such as "Call forwarding") accept incomplete entries. This means you have to add more digits later on when you activate the function by pressing a key. 

Confirm. 

Select and confirm. 

Now press the key to access the function directly. If the function can be turned on and off, such as "Do not disturb", pressing the key multiple times turns the function on and off.

Meaning of LED Signals for Saved Functions:

Call forwarding, Forwarding - trunk, Forward Line, US:Night answer UK:Night Service, Do not disturb, Changeover, Advisory message, Ringer cutoff, HF answerback on/off, Hunt group join/leave, Caller ID suppression, Call wait.term., Waiting tone off, Ring Transfer, Door opener on/off, Control Relay, Ringing group on, Shift Key, UCD (Available on/off, Work on/off, Night answer on/off):
 

Saved function is not active. 

Saved function is active. 

Callback: 

You have not set a callback. 

You have set a callback. 

Mute (on/off): 

The microphone is switched on. 

The microphone is switched off. 

Caller list: 

No calls saved. 

Call request saved. 

Repdial key (internal), Direct station select: 

The other party is not engaged in a call. 

The other party is engaged in a call or has activated do not disturb. 

Flashing rapidly - A caller is trying to reach you, please pick up the phone.
Flashing slowly - A caller is trying to reach another party, who has not yet answered. 

Mailbox: 

No messages present. 

Message(s) present. 

Call key, General call key, Trunk key, MULAP Key, Temporary MSN: 

No call on assigned trunk. 

Active call on assigned trunk. 

Flashing rapidly- A call has arrived on this line; press the key to pick up the call.
Flashing slowly - A call on this line was placed on hold. 

Trunk group key 

At least one trunk is free. 

All trunks in the trunk group are busy. 

View call charges: 

No chargeable calls have been made since the last time call charges were displayed. 

Chargeable calls have been made since the last time call charges were displayed. 

Call forwarding, Forward Line: 

Flashing slowly - Either you or your trunk is the destination of a forwarded call. 

Fax details/answering machine 

No fax received or no message on answering machine. 

Fax received or message on answering machine. 

View number of calls: 

No callers waiting 

Flashing rapidly - Callers waiting (a certain number is exceeded).
Flashing slowly - Callers waiting (a certain number was reached). 

The following functions are assigned to keys which have no LED:
Repdial key (external), Procedure key, Trace call, Speed-dial, Release call, Clear, Lock all phones, Send message, US:Directory UK:Phonebook, Call waiting, US:Connect/Toggle UK:Shuttle, Conference, Speaker call, Retrieve line, Reserve trunk, Release trunk, Temporary Phone, Override, US:Park UK:Call Park, Pickup - directed, Pickup - group, Account code, Show call charges, Radio paging equip, Answer page, Timed reminder, Open door, DTMF dialing, Recall key, Room monitor, Hold key, Consultation, Associated dial, Associated serv., Tel. data service, Relocate