Last nite wheni was at my bed playing with my n191 and accidently i pressed MENU+6+* i got one option FIELD SERV that ask for a 6 digit code and i pressed 123456 then some more option came out like
1. Debug Screen
2. Test call
3. Voice SO
4. Port Map
5. Data Scrn
6. Reverse RC
7.My Phone No
so i ask all u ppl to find out more on all these things
i have tried it only on my sam n191