Filed under: Electronics, music, software — admin @ 10:04 pm February 27, 2010

One of the most fascinating projects that I have been involved it´s the reconstruction of an old Telex machine in order to make a “musical instrument” with it.

/* Note:  This post it´s still under developement ! */


In the end of the year 2009, during an one week “residency” in Oslo,  invited by the artist, musician and pioneer “telex spammer”  Per platou. , I worked on the Telex to add a electric/ mechanic extension to it.

Basically..  I added the Telex an USB port..

The software to reproduce music notes following the “boudot” tape / score, was coded part in Berlin and part in Norway…  I´m still polishing the “letter recognition” thing. But the basic functionality works and it´s really plug & play.


A telex its a technology that appeared in the 30´s and basically allows to send text messages over the telephonic line. It´s a clear precursor of what today we know as “internet”..

The way the Telex work it´s by mechanically encoding/decoding  all the letters and the numbers in a “plain” 5 bit encription. when you type a message in the Telex, first you generate a perforated paper tape that has a middle  continuous file of small holes (used to track the tape) and 5 files more of dots.. Each column represent a “character”, this can be a letter or a number, but also a special messages like “move paper down”, “go back to left margin” “ring the bell”…  This code of 5 bit it´s called “boudot”.

After you have “encoded” your text in the tape, you can insert it in the “reader” and then when you press the “send” button, the Telex will read the tape, write it into paper and send it  to the number you have dialed at an aprox speed of 240 characters per minute (~ 4 per second).


Convert the telex into an experimental musical machine.

1_read the perfored tape and transform the combination of holes into notes/chords/ rythm

2_send midi “syncro” to any midi software

3_being able to control the main speed of the telex

4_add usb “plug and play” implementation into the telex to send the midi notes and the synchrony to any software

5_ add 5 piezo microphones to capture the real sound of the telex while it´s working.


(Extract of a real Skype chat with another Pd programmer while we were trying to figure out how to decode again the boudot into alphabet… )

[16/11/09 19:21:36] João Pais:  0 1 0 0 1
[16/11/09 19:21:40] João Pais: 1 0 0 0  1
[16/11/09 19:22:55] João Pais: l2s -> route 01001 10001 …
[16/11/09 19:23:16] João Pais: strecmp
[16/11/09 19:23:18] João Pais: strcmp
[16/11/09 19:24:09] SErvando Barreiro: 00100
[16/11/09 19:24:15] SErvando Barreiro: 00111
[16/11/09 19:24:51] João Pais: route 00100 00111 01000 …
[16/11/09 19:28:31] João Pais: |0 0 1 0 0(
|                  /[symbol -(
[route 0-0-1-0-0]

pure data




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