Hello, I am using two computers. The serial i/o chip is 16550A based. It is an old hardware and could not find more details. The two serial ports (ttyS0) are connected by a null-modem cable. I am sending a simple string (This is the tester) from one end to another end. I am running 2.6.9 kernel. With 9600 baudrate the receiving end I get either This is the test or This is the test er If I use a baudrate of 19200 or 38400, I get the following string: T<00>his is I interpreted this as a data corruption. So I used 9600 baudrate at both ends. I put a printk debug statement in 8250.c program ( procedure: static void receive_chars(struct uart_8250_port *up, unsigned int *status) ) The printk is after the following line: do { ch = serial_inp(up, UART_RX); Analysis of the received character did not reveal any missing of characters. I don't exactly know the flow of the serial driver functions and hence not exactly knowing the next step in debugging. So I would like to get some guidance/direction/suggestions from others. Also, I would like to have references for a HowTo/architecture of Linux serial driver. Please let me know your input. Any help is appreciated to solve this problem. A. Krishnan -- To unsubscribe from this list: send an email with "unsubscribe kernelnewbies" to ecartis@xxxxxxxxxxxx Please read the FAQ at http://kernelnewbies.org/FAQ