At 2003-12-16 05:34, Peter Vogel wrote: >I'm trying to understand the specifications of an RS-232 receiver. > >Input threshold low minimum = 0.8V >Input threshold high max = 2.4V
Sounds like the specs for the 'TTL side' of the chip. Under 0.8V is low and over 2.4V is high. RS-232 regards below -3V low and above +3V high, if I remember correctly. Usually -12V and +12V are used as outputs, but it's not required, just make sure that at the inputs (after whatever length of cable you use) the signal is still outside of the aforementioned range. >Hysteresis max = 1V I thought that hysteresis meant: voltage change per unit of time but I'm not an expert on analog electronics. I'm also thinking about schmitt triggers and they need a minimum rise or drop in the signal before they change from high to low or the other way round. >So, am I right in concluding that to operate reliably I need to swing >the input over at least -0.2V to 3.4V, or do the threshold specs include >the hysteresis? This conclusion seems to be incorrect in any case. ;-) If you found the specs on the internet, perhaps you could give the experts here the URL? Are you talking about the Maxim MAX232 chip? (Often not the best solution for any problem. ;-) Greetings, Jaap -- Author: Jaap van Ganswijk INET: [EMAIL PROTECTED] Fat City Network Services -- 858-538-5051 http://www.fatcity.com San Diego, California -- Mailing list and web hosting services --------------------------------------------------------------------- To REMOVE yourself from this mailing list, send an E-Mail message to: [EMAIL PROTECTED] (note EXACT spelling of 'ListGuru') and in the message BODY, include a line containing: UNSUB CHIPDIR-L (or the name of mailing list you want to be removed from). You may also send the HELP command for other information (like subscribing).
