This is a reply for the beginning designer. I had one of our designers hardware designers look at your question. His reply is below. John Gulley I think he's on the right track. A parallel termination at both ends will probably work best. Some experimentation may be required. RS-423 uses this approach, but is a balanced signal. For RS-423 the termination goes from the positive leg to the negative leg. With single ended signals assume the other leg is ground. By this I mean that the termination goes from the signal leg to ground. I hope this helps. Rob ______________________________ Reply Separator _________________________________ Subject: DES:I/O Terminations Author: John Gulley at inet8 Date: 6/19/97 9:13 AM Think you can help him along. john ______________________________ Forward Header __________________________________ Subject: DES:I/O Terminations Author: [log in to unmask] (Andreas Olofsson) at Internet Date: 6/18/97 6:50 PM Hi, With the risk of being flamed I will pose a rather simple question here (although I certainly don't know the answer). I am kind of new to board level design, and I have tried for days to figure out how to terminate tranmission lines with I/O devices connected to them. Assuming CMOS I/Os, and rise times of 1 ns, any interconnects longer than about an inch could have serious problems with ringing. I am fairly clear on how to terminate lines with a driver and a receiver. However, I can't figure out how to terminate when you have two I/O pins separated by a transmission line. Would you do parallel termination on both ends? Any thoughts? Thanks, *************************************************************************** * TechNet mail list is provided as a service by IPC using SmartList v3.05 * *************************************************************************** * To subscribe/unsubscribe send a message <to: [log in to unmask]> * * with <subject: subscribe/unsubscribe> and no text in the body. * *************************************************************************** * If you are having a problem with the IPC TechNet forum please contact * * Dmitriy Sklyar at 847-509-9700 ext. 311 or email at [log in to unmask] * *************************************************************************** *************************************************************************** * TechNet mail list is provided as a service by IPC using SmartList v3.05 * *************************************************************************** * To subscribe/unsubscribe send a message <to: [log in to unmask]> * * with <subject: subscribe/unsubscribe> and no text in the body. * *************************************************************************** * If you are having a problem with the IPC TechNet forum please contact * * Dmitriy Sklyar at 847-509-9700 ext. 311 or email at [log in to unmask] * ***************************************************************************