Found this whilst browsing around the web.
Your phone has various functions that can be used by just pressing the keys of your phone or by applying to Türk Telekom for the use of the requested service. With the exception of "Wake-up" and "Call Rejection" services you should contact Türk Telecom Customer Services (444 1 444) for the registration of other features. Please note call forwarding, call forwarding when busy and call waiting features are free of charge.
Redialing: The last number can be redialed by just pressing ** # (each usage costing 1 unit)
Preferential Direct call: Stored numbers can be dialed just by picking up the hand set and pushing *53* then enter the number you want to call and press # (for canceling just press #53#)(each usage costing 1 unit).
Speed dialing: Make quick calls to stored numbers by using the speed dial function. Here's how to do it: Dial *51* then enter a speed dialing number (any number with 2 digits) then push * then enter phone number then push #.
Now you can make your speed dialing call by just pushing **and then the speed dialing number you chose. This function can be cancelled by pressing #51* then the speed dialing number and then # (each number registered costing 2 units)
Call forwarding: All calls can be forwarded to GSM or any other telephone: *21*the number to be forwarded #. For canceling press #21# (registration free of charge)
Call forwarding when busy: When your telephone is busy, you can transfer the waiting calls to any other telephone by: *60*the number to be forwarded #. For canceling press #60 # (registration free of charge).
Call waiting: In order not to miss important calls when you on the line: press *43*. If anybody calls you when you are on line you will hear a beep. Press hang-up button and zero. You will be switched to the second caller. When you want to get back to the first caller again press hang-up button and 0. For canceling press # 43 # (registration free of charge)
Locking the phone: If you don't want anybody use your phone you can lock it for calls. *33* your 4 digit code number *type number # (each number registered 1 unit).
Locking type and type number
Locked for all calls other than fire warning (110) 1
Locked for all calls other than province calls 2
Locked for international calls 3
Locked for international, long distance calls and operator 4
Locked for international calls and operator 5
For canceling press # 33* code number #
Conference call: You can make a conference call up to 6 persons.(Threesome 1 unit, group of five 2 units, conference of six 3 units)
Call rejection: If you don't want to hear your phone ringing, press: *26* for canceling press #26# (each number registered costing 5 units)
Automatic call: If the number you call is busy, press: *37*. Your telephone will dial the number automatically and warn you when it gets the number. For canceling press #37 #.(Each call costs 1 unit)
Wake up service: If you want to wake up at any time of the day, for example 07:30 all you need to do is to press *55*hour and minute (0730) #. For canceling press #55*hour and minute#. (Each program registration 2 units, each usage 3 units)
Quite a few I didn't know of.
