[GreenKeys] Fwd: How the Baudot encoding was selected

[Duncan Brown]

The original "Baudot" code character assignment was quite different from 
the IAT-2 code we know and use. Baudot designed his 5-bit code to be 
easy to learn, since it had to be entered (on the 5-key keyboard) by hand.

Here is a c1900 keyboard & printer manufactured in France and derived 
from Baudot's c1880s patent.




In about 1900, Donald Murray patented a typewriter-style keyboard that 
punched a five-bit pattern into a paper tape. He used Baudot's idea of a 
5-bit code, but reassigned characters so that the most-used characters 
caused the least strain on the machines. He also envisioned 
reperforators and page printers and added the commands for Line Feed and 
Carriage Return that were not in Baudot's original code.

So when we talk about mid 20th century teleprinters using the "Baudot 
code", we are only referring to a 5-bit code.  It would be more accurate 
to refer to it as the "Murray code."

Have fun,

Duncan Brown, K2OEQ
USASA    31J30

i-Telex: 212503

Antique Wireless Assoc. Museum,
   Asst. Curator, Commercial Equipment
(also chief TTY op & repairman)

www.antiquewireless.org



On 21-Dec-22 17:32, Michael Katzmann wrote:
> Yes Dave I've heard this too but I think it might be apocryphal.
> https://www.historyofinformation.com/detail.php?entryid=3496#:~:text=%22Baudot%20invented%20his%20original%20code,and%20Wilhelm%20Weber%20in%201834.
>
> "Baudot's original code was adapted to be sent from a manual keyboard, 
> and no teleprinter equipment was ever constructed that used it in its 
> original form. The code was entered on a keyboard which had just five 
> piano type keys, operated with two fingers of the left hand and three 
> fingers of the right hand. Once the keys had been pressed they were 
> locked down until mechanical contacts in a distributor unit passed 
> over the sector connected to that particular keyboard, when the 
> keyboard was unlocked ready for the next character to be entered, with 
> an audible click (known as the "cadence signal") to warn the operator. 
> Operators had to maintain a steady rhythm, and the usual speed of 
> operation was 30 words per minute."
>
> I think a more plausible explanation is that it's faster to press one 
> key for common letters than multiple keys.
>
> Michael
>
> On Wed, Dec 21, 2022 at 5:11 PM Dave Horsfall <dave at horsfall.org> wrote:
>
>     Probably old hat here, but apparently the hole patterns were
>     selected so
>     that the most common letters had the fewest punches.  A tape
>     fragility
>     issue, or wear and tear on the punches etc?
>
>     -- Dave
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