TTYPUNCH: punch a perforated ITA2 TTY tape

Use this TTYPUNCH emulator to create a PNG or JPEG image of a punched ITA2/Baudot teletype tape.

Just punch in some text below and see.

More Information about this:

These perforated paper tapes were used by teletype machines in civil (GENTEX, AFTN) and military telex networks and telegram services.
The teletype signals may propagate both on wire lines (keying a line current off/on) as well as on radio teletype circuits (called RTTY or RATT, sending the off/on keyed bits in an FSK mode (frequency shift keying) or AFSK mode (audio FSK on a voice transmitter) as two near-by HF frequencies, a 'mark' frequency for the bit-on status (line current on) or a 'space' frequency for the bit-off status (line current off)). A punchhole denotes a 'mark' bit.
The ITA2 telex code is an asynchronous code. On an active circuit, when there is no traffic to send, the circuit is in a constant 'mark' status (line current on). To establish synchronization, each character is preceded by a 'start' bit ('space' status) and trailed by a 'stop' bit ('mark' status), which has a length of at least 1.5 bits.

Example:
ZCZC DE DL4TA RYRYRYRYRYRYRYRY NNNN

ZCZC DE DL4TA
RYRYRYRYRYRYRYRY

NNNN

The ITA2 Telex code (International Telegraph Alphabet No. 2, formerly also known as CCITT No. 2) consists of 5 bits per character which makes 2**5 = 32 code combinations. This is not enough for all Latin letters A...Z, figures 0...9 and punctuation characters, so the code is used twice, in 2 shifts: in "letters shift" 26 codes for the letters A...Z (the letters are here just once, there is no distinction between upper and lower case writing), in "figures shift" 26 codes for the figures and punctuation characters, and the remaining 6 characters in all shifts are shift independent control codes for blank, carriage return (CR), line feed (LF), letters shift (LTRS), figures shift (FIGS) and a possible additional national 3rd shift.
The 5 bits of the code make 5 punch holes per character. Additionally, there is a smaller perforation line (3rd from top) for transportation of the tape in the tape reader.
Only the code bits get punched on the tape, the necessary 'start' and 'stop' bits are generated by the sending telex machine independently on its own. So, the data stream consists of 7.5 bits for each character: 1 'start' bit, the 5 coded character bits, 1.5 trailing 'stop' bits.
The original width of the punch tape is 17 mm.

This ITA2 TTY punch tape emulator understands the following characters:

 letters: A B C D E F G H I J K L M N O P Q R S T U V W X Y Z
 figures: - ? : $ 3 ! & # 8 * ( ) . , 9 0 1 4 ' 5 7 = 2 / 6 +
 control:   [blank]
          < [cr]
          > [lf]
          | [letters shift]
          ^ [figures shift]
          ~ [code no. 32 (national 3rd shift)]

Note: for convenience, this punch emulator program uses a slightly different figures shift character set than the original ITA2 definition, where the figures shift codes corresponding to the letters D is the WRU (who-are-you) function, F, G, H are undefined, J is the bell.
On US-American TTY machines, the figures shift codes corresponding to the letters F, G, H are !, &, #, J is ', S is the bell, Z is ".

Document URL : http://www.kloth.net/services/ttypunch.php
Copyright © 2002-2024 Ralf D. Kloth, Ludwigsburg, DE (QRQ.software). < hostmaster at kloth.net > [don't send spam]
Created 2002-09-19. Last modified 2004-05-12. Your visit 2024-01-20 10:54.37. Page created in 0.0746 sec.

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... the text to be punched on tape.
Output image type (PNG or JPEG)
Punch size