Since you want to "passively" monitor lines why not use a 1489 RS-232 receiver chip for the interface? -----Original Message----- From: Colin Constant Sent: Nov 14, 2003 4:54 PM To: PICLIST@MITVMA.MIT.EDU Subject: [EE]: RS-232 breakout worries The talk here recently about RS-232 breakout devices convinced me that I really should build one of those. I thought, to start, I'd just make a board with a DB9 connector and a header. Then I got to worrying (about the computer this would be attached to). Input pins: should I put resistors in series to protect the computer from ESD? Output pins: should I put resistors in series just in case the outputs get connected to ground? Ground: Do I need to worry about the RS-232 ground getting connected to say +5V. It seems like this shouldn't hurt anything, but I'd like to be sure :-) Thanks folks, Colin _________________________________________________________________ The new MSN 8: smart spam protection and 2 months FREE* http://join.msn.com/?page=features/junkmail http://join.msn.com/?page=dept/bcomm&pgmarket=en-ca&RU=http%3a%2f%2fjoin.msn.com%2f%3fpage%3dmisc%2fspecialoffers%26pgmarket%3den-ca -- http://www.piclist.com hint: The list server can filter out subtopics (like ads or off topics) for you. See http://www.piclist.com/#topics -- http://www.piclist.com hint: The list server can filter out subtopics (like ads or off topics) for you. See http://www.piclist.com/#topics