I need to talk to an Arduino Duemilanove board from a computer over a fairly long distance (100+ ft). USB can't achieve this sort of distance, so I think using the built-in USB port and FTDI converter is out. However, a normal RS-232 serial connection should be able to deal with this distance just fine.
I've seen some references to using pins 0 and 1 (RX and TX) directly for serial connections, bypassing the FTDI chip, but I haven't seen any details on how to implement this. My naive attempt to simply connect tx/rx/gnd to pins 2,3,5 on a serial connector did not work.
If I understand correctly, the microcontroller works with TTL 0/5V signals on these lines, while a computer serial port works with +/- 3 to 15 V. What methods can be used to make standard RS-232 work with the Arduino? I've seen some references to MAX232 chips - is there a particular one that is recommended? I've also seen other PIC microcontroller circuits that use transistors to switch +/-12V for outgoing TX, and a voltage divider for incoming RX. I'd be interested in hearing the pros and cons of the different ways this is commonly done.