http://www.8051projects.net/ Learn to make simple microcontroller projects, pic, 8051, avr and arm projects. download 8051 projects, tutorials, libraries, sample codes. join the microcontroller discussion forum and ask doubts regarding electronics. the best source for 8051 over internet. en-gb 2008-12-02T00:17:40-08:00 contact@nospam.com hourly 1 2000-01-01T12:00+00:00 http://www.8051projects.net/forum-t9410.html 2008-12-02T00:17:40-08:00 hiii all,i need to make interfacing bet. mobilephone (nokia 6100) and MCU ,so i try 1st to connect the mobile with hybridterminal but it not work at all and not work also with nokia pc suit,but it work with logomanger,Is the data cable is responsable for that?if yes haw can i modefay thise cable or make a new one? http://www.8051projects.net/forum-t9410.html 2008-12-02T00:17:40-08:00 Eng_Z Hi Ahmed,I have the same problem with my project and I need help too the phone is nokia 6100 and I have tried many commercial cables (serial ones) with many programs but only logomanager and oxygin did work I need the phone and the cable to work with hyberterminal to be able to send AT-commands from the hyper to the phone, so I tried to make a homemade one but till now it does not work it is still under testthe circuit and the explanation in the following link;http://www.panuworld.net/nuukiaworld/hardware/cables/fbus.htmBut I hope if any one has any experience with that please help http://www.8051projects.net/forum-t9410.html 2008-12-02T00:17:40-08:00 Eng_Z hi Ajay Do you have any experience with that ?and if you have (I hope you have) Does the above circuit work with AT-commands?Waiting your reply,, http://www.8051projects.net/forum-t9410.html 2008-12-02T00:17:40-08:00 Ajay you can directly connect your controller RX and TX with phone as both are going to be on TTL levels. so only three pins of 6100's port tx, rx, and GND. http://www.8051projects.net/forum-t9410.html 2008-12-02T00:17:40-08:00 Eng_Z hi Ajay,Thank you for your reply, I will try that soon and I will tell you the resultsbut what if we make a voltage divider at the RX of the phone to convert the 5v of the micro(Atmel8515)to 3v that because I knew that the phone (6100) voltage level is 3vdoes the 5v harm the phone?thank you http://www.8051projects.net/forum-t9410.html 2008-12-02T00:17:40-08:00 Ajay well just limit the current using resistor and surely a voltage divider is needed. phone is more important http://www.8051projects.net/forum-t9410.html 2008-12-02T00:17:40-08:00 say2paul Ajay wrote ...well just limit the current using resistor and surely a voltage divider is needed. phone is more important Does limiting the current with a resistor means the voltage divider or voltage divider is something else? http://www.8051projects.net/forum-t9410.html 2008-12-02T00:17:40-08:00 Ajay it means voltage drop...voltage divider is when you divide voltage using two resistors..|   V1 |   V2 ||/\/\/\|/\/\/\|  R1      R2V1 = R1 * (Vtotal/R1+R2)V2 = R2 * (Vtotal/R1+R2)