In a message dated 1/6/03 12:42:25 AM, [EMAIL PROTECTED] writes: << > Even if the voltage, due to data transmission is only 1 volt, if it is > a > "+" (positive) 1 volt and you put it to a terminal that is expecting a > "-" (negative) 1 volt, it will smoke, maybe just a little or maybe a > lot. If it doesn't smoke it could just render a few of the component > in the circuit inoperative by shorting out. Like no work anymore.
I'm a self-taught networker. I have wired a few cables up wrong (in the beginning at least) and never managed to blow any of my kit up. I would have thought equipment would have been built with idiot tolerance for reversed voltages, I know a lot of other stuff is. >> Both wrong. But the first is more wrong than the second. If a single-ended circuit, there is only +5 volts and +5 volts Return (AKA, Ground). Place +5 volts on a pin which is positive true logic, then that pin sees "+", ON, "1", whatever; place Ground on that same pin and that pin sees "-", OFF, "0", whatever. Place +5 volts on a pin which is negative true logic (such as a SCSI-N bus), then that pin sees "-", OFF, "0", whatever; place Ground on that same pin and that pin sees "+", ON, "1", whatever. If a differential circuit (such as a SCSI-LVD bus), there is only + several hundred millivolts with respect to a reference, and - several hundred millivolts with respect to that same reference. If the non-dotted terminal is positive with respect to the dotted terminal, then the circuit sees "+", ON, "1", whatever; if the non-dotted terminal is negative with respect to the dotted terminal, then the circuit sees "-", OFF, "0", whatever. Many circuits, contain protection for intentionally reversed voltages. -- Quadlist is sponsored by <http://lowendmac.com/> and... Small Dog Electronics http://www.smalldog.com | Enter To Win A | -- Canon PowerShot Digital Cameras start at $299 | Free iBook! | Support Low End Mac <http://lowendmac.com/lists/support.html> Quadlist info: <http://lowendmac.com/lists/quadlist.shtml> The FAQ: <http://macfaq.org/> --> AOL users, remove "mailto:"; Send list messages to: <mailto:[EMAIL PROTECTED]> To unsubscribe, email: <mailto:[EMAIL PROTECTED]> For digest mode, email: <mailto:[EMAIL PROTECTED]> Subscription questions: <mailto:[EMAIL PROTECTED]> Archive: <http://www.mail-archive.com/quadlist%40mail.maclaunch.com/> Using a Mac? Free email & more at Applelinks! http://www.applelinks.com
