Hi all friends. I use LPC935 for my project and the powersupply for this type is 3.3V. I want to communicate with GSM phone trough UART at 115200b/s with internal RC oscillator @7.373Mhz.The BRGR0 and BRGR1 values are set for 115200b/s(BRGR0=0x30 and BRGR1=0x00).LPC935 recieves the data correctly trough the RxD-pin(pin 1.1)but when sending the data to the phone, the phone doesnot respond to it. When same data is sent trough a datacable from the PC, the phone responds correctly. My question is whether the signal of the TxD of the LPC935 is not high enough to be able to communicate with the GSM. Do i need to put a pull-up or pull-down resistor or do i have to do something else. Im stuck and really need yours help. Any help is very much appreciated Embedded