On Nov 11, 1:27, John K. wrote:
> At 2003-11-10 04:17 PM, Pete Turnbull wrote:
> > I need some help with some HP 2000 BASIC.
> HP 2000 BASIC placed printing characters inside double-quotes (") and
used
> the apostrophe notation for non-printing characters. The apostrophe
was
> followed by the decimal value of the character that belonged at that
point
> in the string. Thus, any character in the extended ASCII character
set
> could be expressed using the apostrophe notation ('0 through '255).
This makes sense.
> The '14 was used to instruct an HP terminal (probably an HP2640,
HP2645, or
> near the end of support for the HP2000 ACCESS, the HP2621 and HP2624)
to
> switch to the alternate (usually line drawing) character set. The
'15 was
> used to switch back to the normal character set.
>From other information about the origin of TREK73 (see Kermit Murray's
page at
http://ch309c.chem.lsu.edu/~kmurray/other/trek73/), and knowing
where my listing came from, I'm pretty certain it was intended to be
run using a Teletype [AK]SR33. On that machine, SO (decimal 14 is
Shift Out) would, as far as I remember, switch to the second colour if
you had a two-colour ribbon. And SI (decimal 15) would shift back.
OK, I can see a use for that, though it's slightly odd in that the
lines where it occurs aren't particularly special, and the text is
bracketed by a pair of '14, not by '14 and '15 as I'd expect. My ASR33
only has a black ribbon, so I can't check if SO is cancelled at the end
of a line (I have a feeling it might be). Oh, well, I better finish
typing and find a way of trying it out...
--
Pete Peter Turnbull
Network Manager
University of York
Received on Tue Nov 11 2003 - 16:04:29 GMT