14 Jan
2011
14 Jan
'11
12:37 p.m.
On 2011 Jan 14, at 7:09 AM, Shoppa, Tim wrote:
Eric wrote:
(In concurrence:)
A former list member, Tom Jennings, wrote a treatise on character code
development from Morse to ASCII
http://wps.com/J/codes/index.html
From this, at the time it was created the Murray code was building on
the principles of the Baudot code (fixed character lengths of 5 'bits'
and simple two-state 'bits'), in contrast to the Morse(-style) codes
(variable length characters and variable length primary symbols).
While the Murray code might better have been referred to as a
'Baudot-style' code, one can surmise that in the context of the times
(early-1900s), the significant point for general reference was not the
details of the encoding but distinguishing it from Morse codes. The
'-style' was implicit or dropped for simplicity of use and it was just
referred to as 'Baudot' code.
Some minor changes were made to the Murray encodings and it became the
ITA #2, but referring to it as Baudot code continued for general
reference. In other words (like so many other things), both terms would
seem reasonable or 'correct' depending on the perspective one is coming
from.
>> There are no Teletypes that use Baudot
code. They use a US variant
>> of
>> the ITA2 five-level code.
>> Baudot code was only used until about 1901. Murray code was used
>> until
>> the 1930s. Everything after that used ITA2.
Tim wrote:
> That's a little like saying nobody
actually uses ASCII since 1968,
we're all really
> Using ANSI_X3.4-1968 or later. Technically
true but not common usage.
Eric wrote:
No, it's not much like that at all. Baudot
code used significantly
different character encodings than ITA2, such that a Baudot device and
an ITA2 device will not interoperate in any meaningful fashion.
ASCII-63, ASCII-67, ASCII-68, and ANSI X3.4 have only minor variations
and will generally interoperate reasonably well.
I'm not disagreeing that the academically correct term is ITA #2.
(Interestingly
most web page hits today call it "ITA 2" or "ITA2" but the 70's
and
earlier
books call it "ITA #2" when they are being pedantic.)
I'm just saying that in its Heyday, if you had to distinguish a 5-level
TTY from a 7-level TTY, the working terms were Baudot and ASCII.
Although
technically incorrect.