How could i know what dct is my nokia?

[fyzmesa]

I bought a nokia 6020 and i want to know if it's a dct-4 a dct-3 or a dct-2.
could you help me please?

[Karim]

DCT-4.
There's no way to "know" you just have to ask somebody who knows.

[fyzmesa]

ok thx, now i have to unlock it, but when i use unlock codes nothing happens, when i put an other sim card it tells me that the phone is locked and ask an unlocking code, so i put codes that nokia free calculator gives me but they doesn't works, i tried 3 times so i guess that it left me only one try before the last that will definitly block my phone. unfortunetly i tried codes set for dct2 and 3 so 2 for nothing. if someone knows how to unlock it by cable (with dku2) it'll be very cool.
so plz help me