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Standard
Telex
  
ITA-2 →
  
MTK-2
Russian Baudot

MTK-2 is a variant of the ITA-2 standard, which adds support for the Cyrillic alphabet. This is done by introducing a third shift character 'RUS' — the other two being the Letter- and Figure-shift. It replaces the NULL code (000·00) of the ITA-2 alphabet, which is no longer available.

Normal text consists of over 50 different characters (26 letters, 10 numbers, 10 punctuation marks and some control codes). In the ITA2 standard, 5 bits are used to represent a character, which means that only 32 different codes can be created (25). As this is insufficient for normal text, most codes are used three times (i.e. have 3 different meanings) and special reserved codes are used to shift between the sets, known as Letters (LTRS), Figures (FIGS) and Cyrillic (RUS).

The letters of the Cyrillic alphabet is mapped onto their Latin equivalent were possible. As Cyrillic has more characters than the Latin alphabet – typically 33 instead of 26 – five figures have been replaced by Cyrillic letters. The Russian symbol ' Ъ ' is discarded, whilst ' Ë ' is replaced by ' E '. The Cyrillic alphabet is selected with the former NULL code (000·00), and is deselected by pressing FIGS (110·11) or LTRS (111·11). CR, LF and SPACE are common to all alphabets.


LTRS-shift is represented by 111·11 (5 holes), so that it can be used to wipe part of a paper tape, without affecting the rest. Normally, a paper tape would start with two LTRS characters, to ensure that the teletype is in Letters-mode. By convention, the holes (bits) in the tape are called channels or tracks and the tape is shown as it would run through the reader away from you.


Encoding
Ltr Letters (A-Z)
Fig Figures (Numbers and punctuation marks)
Rus Russian, Cyrillic
Ctrl Control characters
Hex Hexadecimal code
Bin 1 Binary, Positions of the holes in the paper tape
# Ltr Fig Rus Hex Bin  
0 RUS 00 000·00 Cyrillic shift
1 E 3 Е 01 000·01  
2 LF 02 000·10 Line Feed (new line)
3 A - А 03 000·11  
4 SP 04 001·00 Space
5 S ' С 05 001·01  
6 I 8 И 06 001·10  
7 U 7 У 07 001·11  
8 CR 08 010·00 Carriage Return
9 D Ч Д 09 010·01 Was: ENC (who are you?)
10 R 4 Р 0A 010·10  
11 J Ю Й 0B 010·11 Was: BELL
12 N , Ч 0C 011·00  
13 F Э Ф 0D 011·01 Was: exclamation mark
14 C : Ц 0E 011·10  
15 K ( К 0F 011·11  
16 T 5 Т 10 100·00  
17 Z + З 11 100·01  
18 L ) Л 12 100·10  
19 W 2 В 13 100·11  
20 H Щ Х 14 101·00 Was: currency symbol
21 Y 6 Ы 15 101·01  
22 P 0 П 16 101·10  
23 Q 1 Я 17 101·11  
24 O 9 О 18 110·00  
25 B ? Б 19 110·01  
26 G Ш Г 1A 110·10 Was: & or @
27 FIGS 1B 110·11 Figures (Shift on)
28 M . М 1C 111·00  
29 X / Ь 1D 111·01  
30 V ; Ж 1E 111·10  
31 LTRS 1F 11·111 Letters (Shift off)
Other standards
References
  1. ECMA, Standard ECMA-10 for Data Interchange on Punched Tape
    2nd Edition. July 1970.

  2. Wikipedia, Punched tape
    Retrieved January 2015.

  3. R&S Manual of Transmission Methods
    4070.0711.02-03. Rohde & Schwarz, München (Germany) 2014. pp. 327-329.
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Crypto Museum. Created: Tuesday 20 January 2015. Last changed: Saturday, 06 March 2021 - 16:09 CET.
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