Non-POSIX parity (mark/space) with Python-Serial on Linux.

gene heskett gheskett at wdtv.com
Mon Nov 21 13:33:17 EST 2011


On Monday, November 21, 2011 01:28:16 PM David Riley did opine:

> On Nov 21, 2011, at 12:25 PM, gene heskett wrote:
> > And that is 9600 baud 8n1 on both ends.  Ascii is normally 7 bit and
> > will have a low 8th bit if fed normal ascii data, so how is the 8th
> > bit getting set other than purposely setting 7M1 on the other end of
> > the cable?
> 
> That's what I thought the OP was doing; it sounds like he's trying to
> receive 7M1 in Minicom using 8N1 on the terminal and getting garbled
> data because the high bit is set (because the other end is sending
> 7M1).  I never meant to imply that 8N1 would give garbled data if both
> ends were set to it; indeed, that's pretty much standard communications
> settings for short cables in low to moderate noise environments.  If
> anyone else read it that way, that's not what I meant. :-)
> 
> - Dave

I think that getting the other end off 7M1 was what I was saying.  Trying 
to attack the bad data after capture by writing code always seems extremely 
masochistic to me.

The amount of miss-understanding that seems to pervade rs-232 
communications is mind boggling at times.  The tech itself is so old it is 
being forgotten!

Cheers, Gene
-- 
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