missing characters

missing characters

[Brian Tew]

Well well, after years of mumbling about it I finally
got linux--hoo ray!
It is old, rh5.2, but the 7.2 cd was scratched or something.
And debian wouldn't recognize my ethernet card.

I am using an old versabrailler for output.
It does pretty well, but it drops some characters.
I have used versabraillers for seven years, and I never got them working
right any faster than 2400 baud.
I have played with the serial parameters ad nauseum, but 2400 is it.
So:

How can I slow linux down to 2400 baud?
Is it the setserial command?
These serial ports in the vb are probably 16450 or maaybe older.
I have tried several setserial options, but no success so far.

Can I use setserial on /dev/ttyS0, or must I use it on cua[something}?

I would appreciate any suggestions or alternate approaches or info.

Thanks.

Brian Tew

Re: missing characters

[Dave Mielke]

[quoted lines by Brian Tew on March 16, 2002, at 07:33]

>How can I slow linux down to 2400 baud?

stty </dev/ttyS0 2400

The stty command works on the device which is attached to its standard input.

>These serial ports in the vb are probably 16450 or maaybe older.

You can query that with: setserial /dev/ttyS0

-- 
Dave Mielke           | 2213 Fox Crescent | I believe that the Bible is the
Phone: 1-613-726-0014 | Ottawa, Ontario   | Word of God. Please contact me
EMail: dave@mielke.cc | Canada  K2A 1H7   | if you're concerned about Hell.
http://familyradio.com

Re: missing characters

[L. C. Robinson]

On Sat, 16 Mar 2002, Brian Tew wrote:

> Well well, after years of mumbling about it I finally got
> linux--hoo ray!  It is old, rh5.2, but the 7.2 cd was scratched
> or something.  And debian wouldn't recognize my ethernet card.

You should upgrade anyway, or at least get all the updates.  I
don't think RH is issuing security updates for 5.2 anymore: I
haven't seen any announcements for that version for a long time.
With the number of updates for old versions, usually upgrading is
easier anyway (Red Hat automates the upgrades off a new install
disk).  Get your cheap distribution CDs from cheapbytes.com,
lsl.com, Linux Central, or the like (about $2 per disk, plus
shipping is approximately $5).  Better yet, go to
http://www.tummy.com/krud/ and get disks with with all the
updates already included, for a bargain price.
 
> I am using an old versabrailler for output.  It does pretty
> well, but it drops some characters.  I have used versabraillers
> for seven years, and I never got them working right any faster
> than 2400 baud.  I have played with the serial parameters ad
> nauseum, but 2400 is it.  So:
> How can I slow linux down to 2400 baud?  Is it the setserial

Even 1200 should be plenty fast enough for interactive use:
To set:
rootprompt# stty 1200 < /dev/ttyS0
To read:
rootprompt# stty speed < /dev/ttyS0
1200
rootprompt# echo "Can you hear this?" > /dev/ttyS0

> Can I use setserial on /dev/ttyS0, or must I use it on
> cua[something}?

The cua stuff is obsolete, probably even for rh5.2.

Setserial is mostly for setting irqs and ioports for unusual
multiport cards, and odd serial setting, shared IRQ 4, 8, and 16
port smart cards, etc.  You don't need it for com1 (/dev/ttyS0),
or com2 (/dev/ttyS1).

But the above stuff is probably only useful early in the boot
process (scripts), so you can see boot messages, or for testing.

You want to add a something like:
"console=ttyS0,1200 console=tty0"
to your "append= " lines for your bootmanager image
config (like lilo), and: 
serial  = 0,9600n8
in the global options area.
See /usr/doc/kernel-doc-2*/serial-console.txt for details.

However, once booted, you are presented with a login prompt by
the getty program, and the getty controls all terminal settings,
and can configure them all, so you presumably have, or must add,
a line in /etc/inittab something like (do: "man getty" for
details):

t0:2345:respawn:/sbin/getty -r1 ttyS0 DT2400
or
t0:2345:respawn:/sbin/getty -r1 ttyS0 DT1200 [maybe: vt100]

The "DT1200" is really a label for a config line in
/etc/gettydefs, and there is none for that speed.  So you just
take the DT9600 line and change all the instances of 9600 to the
speed you want (just add these config lines to your gettydefs):

# 2400 baud Dumb Terminal entry:
DT2400# B2400 CS8 CLOCAL # B2400 SANE -ISTRIP CLOCAL #\07\n\07\n\07\n@S @B Enter your login name: #DT1200

# 1200 baud Dumb Terminal entry:
DT1200# B1200 CS8 CLOCAL # B1200 SANE -ISTRIP CLOCAL #\07\n\07@S @B What's yer' name, Bub?: #DT300

# 300 baud Dumb Terminal entry:
DT300# B300 CS8 CLOCAL # B300 SANE -ISTRIP CLOCAL #Slow terminal\n \07 @S @B login name: #DT2400

# Config end -- don't leave out the blank lines, and don't fold
# them.

With this closed set chain, you can shift buad rates (from the
man page "man gettydefs", for the last field in the line):

   next-label    This indicates the next label of the entry in the table that
                 getty should use if the user types a <break>  or  the  input
                 cannot  be  read.   Usually,  a  series of speeds are linked
                 together in this fashion, into a closed set.  For  instance,
                 2400  linked  to 1200, which in turn is linked to 300, which
                 finally is linked back to 2400.

Note that I have added some bel characters (\07) to the login prompt,
in hopes your terminal will respond audibly (the VGA console won't,
unless you use mgetty, with a very different config), and "@B"
for the current baud rate to be printed.

Note that modern versions of Red Hat log all the bootup stuff in
files found in /var/log/, so you can examine it at your leisure.
You only care about real time boot messages if the boot hangs
somewhere, without completing (rare), and then you only probably
care about the last line or two.  All that junk during boot just
clutters up the screen and confuses newbies, so much of it can be
silenced with a proper config these days (logged anyway), and
that is a good trend.

Let us know how it goes.

LCR

-- 
L. C. Robinson
reply to no_spam+munged_lcr@onewest.net.invalid

People buy MicroShaft for compatibility, but get incompatibility and
instability instead.  This is award winning "innovation".  Find
out how MS holds your data hostage with "The *Lens*"; see
"CyberSnare" at http://www.netaction.org/msoft/cybersnare.html

Re: missing characters

[Cheryl Homiak]

Probably debian didn't recognize your ethernet card because the default kernel
didn't have it compiled in. Some of that might depend on what version of debian
you had also, though some card won't be recognized and you then either have to
get the module or recompile your kernel. However, it's probably not something
you wanted to do right at the beginning of linux use.

As for the "versabrailler" (I'm not sure if you are feferring to the vbII+ or
something else) I haven't used it with linux, but I did use it connected to my
computer in DOS to copy files, etc. I did get it up to 9600 baud; unfortunately
I don't have it out and can't replicate what I did to accomplish this. I know it
had something to do with the dc-in or out and the dts settings and I did have to
play with it somewhat. If I get really ambitious I'll haul it out at some point
and see if I can figure it out.

Re: missing characters

[Dave Mielke]

[quoted lines by Cheryl Homiak on March 16, 2002, at 23:18]

>I don't have it out and can't replicate what I did to accomplish this. I know it
>had something to do with the dc-in or out and the dts settings and I did have to
>play with it somewhat.

That sounds like you were enabling what's known as "hardware flow control".
To be effective, it needs to be on on both ends.  I don't know how to turn it
on for the VB. For Linxu, however, you do it with the command:

    stty </dev/ttyS0 crtscts

-- 
Dave Mielke           | 2213 Fox Crescent | I believe that the Bible is the
Phone: 1-613-726-0014 | Ottawa, Ontario   | Word of God. Please contact me
EMail: dave@mielke.cc | Canada  K2A 1H7   | if you're concerned about Hell.
http://familyradio.com

Re: missing characters

[Cheryl Homiak]

Is the vb supported then, and is it under the TSI drivers? Because it wasn't
listed in the README for TSI as far as I saw.

Re: missing characters

[Cheryl Homiak]

Well, reading the TSI driver documentation, the really old VBs aren't supported,
which comes as no surprise. So you must be using something newer and i can't
help you there. Sorry, I must have misunderstood what you were using.

Re: missing characters

[Lloyd G. Rasmussen]

If you are transferring to tape, the tape-based VersaBrailles can't
actually handle data in Computer Braille mode much faster than 1200 baud.
They go a little faster if you're using binary braille mode, but nobody's
going to use that mode nowadays.  So regardless of the baud rate on the PC
side, you must have handshaking enabled.  I don't know the limits of the
disk-based VersaBrailles which came later.

At 11:18 PM 3/16/02 -0600, you wrote:
>Probably debian didn't recognize your ethernet card because the default
kernel
>didn't have it compiled in. Some of that might depend on what version of
debian
>you had also, though some card won't be recognized and you then either
have to
>get the module or recompile your kernel. However, it's probably not something
>you wanted to do right at the beginning of linux use.
>
>As for the "versabrailler" (I'm not sure if you are feferring to the vbII+ or
>something else) I haven't used it with linux, but I did use it connected
to my
>computer in DOS to copy files, etc. I did get it up to 9600 baud;
unfortunately
>I don't have it out and can't replicate what I did to accomplish this. I
know it
>had something to do with the dc-in or out and the dts settings and I did
have to
>play with it somewhat. If I get really ambitious I'll haul it out at some
point
>and see if I can figure it out.

Braille is the solution to the digital divide.
Lloyd Rasmussen, Senior Staff Engineer
National Library Service f/t Blind and Physically Handicapped
Library of Congress    (202) 707-0535  <lras@loc.gov>
<http://www.loc.gov/nls>
HOME:  <lras@sprynet.com>       <http://lras.home.sprynet.com>

Re: missing characters

[Brian Tew]

Wow guys, this is fantastic!  Thanks to you all.

I am using a vbii+.  It.s parameters are controlled thru a
menu system which is built in.

For the moment I am happy just to get it working so I can read
stuff without having to guess at missing characters.
I am saving all this other good info, and will experiment with it
whenever i need some more grief in my life, smile.

Thanks again to all.
I am now getting perfect output.