[GreenKeys] 100 Speed ITTY Channel

[Jim Haynes]

On Sat, 18 Dec 2010, Til128 at aol.com wrote:
>
> Would anyone  (especially the people on the other side of the pond) have a
> problem with  expanding the line length of ITTY that is running at 100WPM to
> a 72 character  line length??
>
> If so, what would be the absolute maximum  length?
>
A nice thing about living in the computer age is that it is easy to be
fairly smart about dealing with line length.  Seems like some numbers
I have heard are to ring the margin bell at 67 spaces with the idea of
a maximum line length of 72, or ring the bell at 72 for a maximum
length of 77.  For a sprocket-feed Teletype the width of the paper is
8-1/2 inches including the edge strips.  That gives you 7-1/2 inches
of paper to write on if you are going to tear off the edge strips.

It was not until quite late in the game that customers demanded paper that
would be 8-1/2 inches wide after the edge strips were torn off, so the
engineers at Teletype had a hard time but succeeded in making a sprocket
feed platen kit for the 28/35 that would allow 9-1/2 inch wide paper
including the edge strips.  If only we had a time machine and could go
back and whisper in Sterling Morton's ear that he should make the platen
an inch wider on the Model 15!  One reason for the wider paper was to
get the standard 8-1/2 x 11 sheet without the edge strips; another was
to be able to print all 80 columns of a data processing card record on
a single line.

But we have a lot of the original sprocket feed machines out there which
accomodate only 7-1/2 inches between the edge strips, which would give
us a maximum line length of 75 characters using 10 characters per inch
as is most common.  I just pulled a sheet from a sprocket-feed machine
in my collection and find that it is set up for a left margin of about
13/16" (from the edge of the paper, not from the edge of the strip).
This allows 6-15/16 for the typed line, if centered on the paper, or a
length of 69 characters if margins are equal on both sides.  Maybe you
could let it go to 72 characters, by encroaching on the right margin, or 
even a few more by readjusting the left margin.  I didn't check the
right margin setting.

When I say we can be smart about it with a computer, I mean we can see
where the last word on the line will end and insert a CR-LF sequence
wherever needed to prevent exceeding any line length we choose.  Or we
could even hyphenate, but that may involve more smarts than we want
to invest.

Anyway, it seems that at least in the U.S. the sprocket feed possibility
limits us to an absolute maximum line length of 75 characters, because
that is as wide as the platen is.  While sprocket feed is not popular,
I think we must accomodate it because that is the only kind of machine
some users will have.  A 72 character limit would be a little more
comfortable; and with a computer as signal source it can be rigidly
enforced.