[GreenKeys] Baudot code variations

[gil smith]

Hi Bill, Tom, Henning, and gang:

I know, we have been through this before.  I have some questions about 
baudot code variations -- you guys can probably shed some light on 
this.  Bill, you said something about using Tom's code conversions in 
RTTYArt, and then included the code table shown below (the table notes were 
not included).

Your table shows separate sets for ITA2 and Telex.  And you show a Mil 
version, which appears to be what is generally referred to as USTTY.

I thought I had made sense of this a few years ago, but now I wonder 
whether I got it correct:
http://www.baudot.net/tty/docs/smith--teletype-codes.pdf

My understanding is the following timeline:

1874:  ITA1 defined by CCITT -- this is the original "baudot" code designed 
by Gauss & Weber, used with the finger-actuated Baudot Multiplex System in 
France/England.

1901:  Murray Code, as used in early Creed machines.

1930:  ITA2 defined by CCITT (as an evolution of the Murray code), and is 
the code used for international Telex service.

19??:  USTTY (American Teletypewriter code) derived as variation of ITA2, 
and used  in US for commercial and military systems.

As I understand it, the original Baudot code and the Murray code fell from 
use, leaving two almost identical codes (ITA2 and USTTY) -- these had 
variations on the FIGS characters of D, F, G, H, J, S, V, and Z.   For both 
of these codes, some of these figs chars were modified for specific 
applications, but there was a "typical" USTTY, and a "typical" ITA2.

But I now have some questions:

- Did the Telex service use a variation of ITA2, or did a Telex code evolve 
in parallel?  Who originally introduced telex service -- was it 
Siemens?  In what year did telex debut?

- Who was responsible for defining the American Teletypewriter code -- 
Teletype Corp?  Is USTTY an official designation, or more of recent term?

- How can I reconcile the discrepancies in the tables below?

 From Bytheway:
        ITA2    Telex      Mil
------------------------------------------
D      $(1)     wru       $
F      %(2)     $         !
G      &(2)     &         &
H      #(2)     #         stop
J      @(3)     bell      '
S      '(3)     '         bell
V      =        ;         ;
Z      +(4)     "         "
Note 1: ?
Note 2: ?
Note 3: ?
Note 4: ?


 From Smith:
        ITA2/Telex    USTTY
------------------------------------------
D      #/wru           $
F      @(1)            !
G      *(1)            &
H      $(1)            #/stop
J      bell            '
S      '               bell
V      =               ;
Z      +               "
Note 1:  Technically undefined, but had these common symbols.

thanks,

gil


At 11:08 PM 1/19/2005, you wrote:
>A snippit from the RTTYApp source code:
>
>/************************************
>            ITA2    Telex Mil.
>No. Letter Figure  Fig.  Fig.   ITA2
>--- ------ ------  ----- -----  -----
>  1   A      -      -     -      YYBBB
>  2   B      ?      ?     ?      YBBYY
>  3   C      :      :     :      BYYYB
>  4   D      $(1)   wru   $      YBBYB
>  5   E      3      3     3      YBBBB
>  6   F      %(2)   $     !      YBYYB
>  7   G      &(2)   &     &      BYBYY
>  8   H      #(2)   #     stop   BBYBY
>  9   I      8      8     8      BYYBB
>10   J      @(3)   bell  '      YYBYB
>11   K      (      (     (      YYYYB
>12   L      )      )     )      BYBBY
>13   M      .      .     .      BBYYY
>14   N      ,      ,     ,      BBYYB
>15   O      9      9     9      BBBYY
>16   P      0      0     0      BYYBY
>17   Q      1      1     1      YYYBY
>18   R      4      4     4      BYBYB
>19   S      '(3)   '     bell   YBYBB
>20   T      5      5     5      BBBBY
>21   U      7      7     7      YYYBB
>22   V      =      ;     ;      BYYYY
>23   W      2      2     2      YYBBY
>24   X      /      /     /      YBYYY
>25   Y      6      6     6      YBYBY
>26   Z      +(4)   "     "      YBBBY
>27  cr      cr     cr    cr     BBBYB
>28  lf      lf     lf    lf     BYBBB
>29  ls      ls     ls    ls     YYYYY
>30  fs      fs     fs    fs     YYBYY
>31  sp      sp     sp    sp     BBYBB
>*************************************/
>/* finis */
>
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