Hi, Right Now I need to write a simple C code to control the serial / parallel port under linux working like this: Detect there is an input signal / voltage change and send some output signal / voltage accordingly, eg: if DSR is detected to be high, I want to set RTS to be high as well; if RI is detected to be high, I want DTR set to be low etc. I have read the Serial-How to and Serial programming-How to, however I am still not so clear regarding to this simple programming. Could anyone direct me some useful references / codes regarding to this project? Thanks & Best Regards, Johnny Xing -- To unsubscribe from this list: send the line "unsubscribe linux-serial" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html