cctalk Digest, Vol 70, Issue 3

Dave McGuire mcguire at
Wed Jun 3 10:37:54 CDT 2009

On Jun 3, 2009, at 12:06 AM, Jay West wrote:
> These devices had a lot of trouble with RS423, where the voltage  
> was much less than RS232. I don't recall the exact numbers but  
> RS232 was something about 12V swings

   +/- 15V

> and RS423 was about 3.5V swings. Other than that, the two were  
> pretty much identical. People often connected RS423 to 232 devices  
> with no problem at all. But those devices that expected power from  
> DTR or pins 9 or 10 (on a DB25) had a bit of difficulty when  
> plugged into a rs423 port.

   Some Sun systems have jumpers to switch their serial ports between  
RS232 and RS423 modes.


Dave McGuire
Port Charlotte, FL

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