From: Eric Scace (firstname.lastname@example.org)
Date: Wed Jan 07 2004 - 15:11:20 EST
Your 7-bit paper tape system was rather unusual, actually, and was not a Telex system.
Telex systems used what was then termed a "5-level code"; i.e., 5 bits. The code was often called "baudot" but its formal name
was International Telegraph Alphabet #2 (ITA2). It was standardized by the International Telegraph Union (now International
Telecommunications Union, the second-oldest international treaty body and now a specialty agency of the UN). ITA2 provided 32 code
points. Several of these were reserved for special functions: carriage return, line feed, "letters" (forced a shift into letters
case for subsequent characters), "figures" (forced a shift into figures and punctuation for subsequent characters), space and
"blank". The remaining 26 code points represented A-Z (in letters case) and punctuation, digits, and other special symbols (vulgar
fractions, meteorological symbols, bell signal, etc depending on local conventions). These systems used paper tape with 2 holes, a
tractor hole for feeding the tape, and then 3 holes in a column; each of the 5 holes represented one of the bits in the 5-bit
Later, ASCII paper tape systems became common; many of these used 3 holes, a tractor hole, and 5 holes to represent 8-bit
encodings (including a parity bit).
"7-level" tape systems were used in some special applications. Some of the ones that I encountered were based on ASCII without
the 8th parity bit; others used special encodings to control typesetting equipment.
Two-level tape systems were used throughout the first six decades of the 20th century to key submarine telegraph cables.
All of these tape systems were mechanisms for storing information. They aren't alphabets.
-- Eric Scace
From: email@example.com [mailto:firstname.lastname@example.org]On
Behalf Of Anto'nio Martins-Tuva'lkin
Sent: 2004 January 6 15:05
Subject: Punched tape (was: "Re: American English translation of
On 2003.12.19, 00:24, Carl W. Brown <email@example.com> wrote:
>> I'm a programmer, and I'm older than most programmers. I'm old enough
>> to remember punched paper tape ...
> Yes I worked with paper tape as well. I even worked on one machine
> that I would write programs on paper tape loops.
Well, I'm only 34 but I did work with one of these, on a telex machine
for terminal. I still keep some reels of tape, punched with my some of
high school stuff.
Anyway -- it was space for three wholes, the small whole for the tractor
wheel, and space for four more, IIRC.
|O OoOO |
|O oOOO |
| OOo O O|
|OO oOO |
| O o OO|
|O Oo OO |
| OOo OOO|
|O OoO |
| OOo OOO|
|O o OOO|
Any bells ringing? Wouldn't this be a nice "complete" set of chars to be
encoded, a la Braille patterns?...
António MARTINS-Tuválkin | ()|
Rua Alberto Bramão, 8-1º d.to |
PT-1700-132 LISBOA Não me invejo de quem tem |
+351 934 821 700 carros, parelhas e montes |
http://www.tuvalkin.web.pt/bandeira/ só me invejo de quem bebe |
http://pagina.de/bandeiras/ a água em todas as fontes |
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