30 Jan
2014
30 Jan
'14
1:44 a.m.
On Jan 29, 2014, at 6:54 PM, Fred Cisin <cisin at xenosoft.com> wrote:
True. Until you get a double bit error, of course. And that requires parity errors to
produce a distinctive error indication, as opposed to simply causing the character to be
ignored. I don?t know what old style printing terminals did. (It sounds like the ASR33
never did parity on receive.) What you describe did appear in the PLATO terminals, which
indeed had a crude NAK and retransmit scheme that helped with modest link error rates.
paul
All parity can
do is convert garbled characters into missing characters.
If you are sitting there reading text interactively, a garbled character
is no big deal, and you can ignore it/interpolate what the correct one
should be, and not care.
But, there can exist situations where KNOWING that a character is wrong is
more important, perhaps enough so that you would rather repeat the entire
transmission until you get a copy with no errors.