9 May
2014
9 May
'14
1:35 p.m.
There are two questions here.
One is physical format: placement and size of holes and width of
tape. I know of 2, 5, 6, and 8 bit tape. Hole pitch is 0.1 inch, and
the feed hole is small while the data holes are bigger. (I don?t know
the sizes but all the ones I?ve seen are cosistent.)
Herr's a spec I extracted from the service manaul for my Facit 4070 many
years ago....
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My Facit 4070 punch service manual gives some specifications of the paper
tape. They're in milimetres (which is crazy, because the original
dimensions were almost certainly specified in inches), but here goes.
I'll convert some of them to inches as well...
Tape widths :
5 track : 17.46+/-0.08mm (11/16")
6 track, 7 track, 6 track typesetter tape : 22.23+/-0.08mm (7/8")
8 track : 25.40+/-0.08mm (1")
Now, for all but typesetter tape, each row across the tape consists of 3
data holes, a smaller sproket hole, and then 2/3/4/5 data holes,
depending on the number of tracks. The edge of the tape nearest to the
3-holes is the reference edge.
The sprocket hole centre-line is 9.96+/-0.1mm (about 25/64") from the
reference edge. The holes are spaced at 2.54+/-0.05mm(0.1") multiples
from the sprocket holes. And the rows on the tape are
also spaced at
2.54mm (0.1") multiples.
In other words, the centres of the holes on the tape lie on a 0.1" * 0.1"
grid.
Data holes are 1.83 +/-0.05mm in diameter (72 thou). Sprocket holes are
1.17 (+0.05,-0.025)mm in diameter (46 thou).
Typesetter tape is the odd one. It's 6 track, with a line of sprocket
holes almost down the middle of the tape - 11.02+/-0.1mm from the
reference edge (just unde 7.16"). I wonder if this is a typo, and that
the sprocket track should be _on_ the centre line (11.12mm from the
reference edge).
Hole spacings and diameters are as above, apart from the fact that
instead of the center line of the sprocket holes and data holes lining
up, the leading edge does. In other words, the centres of the sprocket
holes are displaced 0.33+/-0.02mm towards the front end of the tape.
-----------------------------------
2 bit is Wheatstone, for encoding Morse code. 5 bit
is ?Baudot?,
i.e., Murray code, the older telegraph system. 6 bit is for early
Ste normal code for 5 level tape is ITA2. This is often mis-named Baudot
r Murray code, but is actually different to both of them.
Baudot code was sued on a 5 lever chording keyboard for the Baudot
Quadruplex system. The encoding is totally differnet ot the others,
Murray code was used on early (1920s) teleprinters, the main diffference
as agaisnt ITA 2 is that there is no separate space chracter, rather ht
there is a 'letters space' and a 'figures space' which advanec on print
position and set the apporpriate shift. There are no seprate shift
chracters either. So you actually coulding prrint '1A48FC' on such a
machine it would be '1 A 48 FC'.
automated typesetters (automated Linotypes or early
phototypesetters).
8 bit we all know.
Do we? 8 level tape was used for all sorts of thigns (ASCII (maybe with a
parity bit), EBCDIC, binary data, etc
FWIW, Iv'e yet to see a punch or reader that does any translation on the
data. You send it 8 bits, it punchs that pattern of holes ('1'= hole),
ditto for reading. It's up to your host machine to get the right data to
the punch.
Oh yes, there is much wider tape (19 channels???) for Monotype
machines. I know nothing about those other than the brief reference I
saw in the excellent book ?Travels in Computerland.
SOmehwere I have the handbook for the Monotype Caster. I don't think it
incldues the tape encoding, though (tIt does include dismantling and
repair instructions)
The other question is encoding. 2 channel tape is Morse (specifically
International Morse, it can?t encode American Morse). 5 channel is
Baudot/Murray, which actually comes in a half dozen variations that
generally affect just the ?figures shift?. channel also comes in a pile
I seem to rememebr that ITA2 has 3 of 4 of the 'figures' shift'
characters unasigned for local usage.
of variations, for example one used for stock listings
which has lots of
different fractions. And 8 channel can encode 7 or 8 bit codes (and
probably even 6 bit codes on old computers that used that), anywhere
from ASCII to t he many Flexowriter codes to BCD and EBCDIC.
As for the original question: a one inch tape machine from CNC
equipment should be just like any other 8 bit tape as far as the
physical aspects are concerned. So you should just need to worry about
the electrical interfacing.
Indeed.
-tony