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I am trying to send strings of data to a customer display connect to
/dev/tty2a in Openserver 5.0.5. The use manual explains how to do this in
dos, but I want to test in out in unix. The manual says to do the following
dos commands:

mode com1 96,n,8,1
type con>com1

then type "!#1ABCDEFGH" and press enter. The display will show "ABCDEFGH"
on the first line. Press Ctrl-C to end.

In dos, I can sit there all day and type in various strings and it works,
but I don't know how to do this in unix. I believe that I have the settings
for tty2a set correctly as I can type echo $string > /dev/tty2a and it
displays. The problem with this testing is that the device has to be reset
after each line because it needs a cr/lf to end one line and begin accepting
another.

Any help is greatly appreciated.

Justin


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"justin" <justin_robbs@NO_SPAMhotmail.com> wrote in message
news:bdcjh4$n87$1@news.tdl.com...
> I am trying to send strings of data to a customer display connect to
> /dev/tty2a in Openserver 5.0.5. The use manual explains how to do this in
> dos, but I want to test in out in unix. The manual says to do the
following
> dos commands:
>
> mode com1 96,n,8,1
> type con>com1
>
> then type "!#1ABCDEFGH" and press enter. The display will show "ABCDEFGH"
> on the first line. Press Ctrl-C to end.
>
> In dos, I can sit there all day and type in various strings and it works,
> but I don't know how to do this in unix. I believe that I have the
settings
> for tty2a set correctly as I can type echo $string > /dev/tty2a and it
> displays. The problem with this testing is that the device has to be
reset
> after each line because it needs a cr/lf to end one line and begin
accepting
> another.
>
> Any help is greatly appreciated.
>
Read the man page for echo
echo $string\r\n

Ron

On Wed, Jun 25, 2003 at 10:44:19AM -0600, justin wrote:
>I am trying to send strings of data to a customer display connect to
>/dev/tty2a in Openserver 5.0.5. The use manual explains how to do this in
>dos, but I want to test in out in unix. The manual says to do the following
>dos commands:
>
>mode com1 96,n,8,1
>type con>com1
>
>then type "!#1ABCDEFGH" and press enter. The display will show "ABCDEFGH"
>on the first line. Press Ctrl-C to end.
>
>In dos, I can sit there all day and type in various strings and it works,
>but I don't know how to do this in unix. I believe that I have the settings
>for tty2a set correctly as I can type echo $string > /dev/tty2a and it
>displays. The problem with this testing is that the device has to be reset
>after each line because it needs a cr/lf to end one line and begin accepting
>another.

The ususal answer is ``there's more than one way to do it''. The Unix
``write'' command is traditionally the way this is done.

Writing directly to a user's tty device may work, but probably won't on a
properly configured system since it has many security implications. (how
would you like to be running as root and have your F1 key reprogrammed to
send ``rm -fr /'')?

Things are muth more compilicated in a multi-user environment than on the
average DOS/Windows machine where there's only one user with one console
device. Even if I'm running an *ix box from the console, there are 12
different ttys I might be on so how do you know which one to write to (when
I was running Xenix I used all 12 of them)?

Bill
--
INTERNET: bill@Celestial.COM Bill Campbell; Celestial Software LLC
UUCP: camco!bill PO Box 820; 6641 E. Mercer Way
FAX: (206) 232-9186 Mercer Island, WA 98040-0820; (206) 236-1676
URL: http://www.celestial.com/

``It is better to die on your feet than to live on your knees!''
-- Emiliano Zapata.

-snip-

> Writing directly to a user's tty device may work, but probably won't on a
> properly configured system since it has many security implications.

I am just trying to write a string of data to an output only device
connected via a serial port.

>(how would you like to be running as root and have your F1 key
>reprogrammed to send ``rm -fr /'')?

That would suck. I have done enough stupid stuff myself without having to
worry about that.

One time running as root I typed
l /tmp
and thought I don't need that stuff so I typed
rm -fr *
and walked away to get a drink, unfortunately, local dir was /
not pretty.

However, since this is just a customer display for a cash register, I don't
think there is anything to worry about.

justin


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On Wed, Jun 25, 2003 at 12:19:51PM -0600, justin wrote:
>
>-snip-
>
>> Writing directly to a user's tty device may work, but probably won't on a
>> properly configured system since it has many security implications.
>
>I am just trying to write a string of data to an output only device
>connected via a serial port.
....
>However, since this is just a customer display for a cash register, I don't
>think there is anything to worry about.

Writing to a serial port compilicates things a bit since one has
to insure that it's parameters are set correctly (e.g. baud rate,
parity, etc.) -- something like:

stty 9600 cs8 -onlcr clocal < /dev/tty1a

The stty command allows you to set how the end-of-line stuff is
handled as well, and can be used to automatically supply CRLF.

Bill
--
INTERNET: bill@Celestial.COM Bill Campbell; Celestial Software LLC
UUCP: camco!bill PO Box 820; 6641 E. Mercer Way
FAX: (206) 232-9186 Mercer Island, WA 98040-0820; (206) 236-1676
URL: http://www.celestial.com/

Government is actually the worst failure of civilized man. There has
never been a really good one, and even those that are most tolerable
are arbitrary, cruel, grasping and unintelligent.
-- H. L. Mencken

"Bill Campbell" <bill@celestial.com> wrote in message
news:20030625114331.B26393@barryg.mi.celestial.com ...
> On Wed, Jun 25, 2003 at 12:19:51PM -0600, justin wrote:
> >
> >-snip-
> >
> >> Writing directly to a user's tty device may work, but probably won't on
a
> >> properly configured system since it has many security implications.
> >
> >I am just trying to write a string of data to an output only device
> >connected via a serial port.
> ...
> >However, since this is just a customer display for a cash register, I
don't
> >think there is anything to worry about.
>
> Writing to a serial port compilicates things a bit since one has
> to insure that it's parameters are set correctly (e.g. baud rate,
> parity, etc.) -- something like:
>
> stty 9600 cs8 -onlcr clocal < /dev/tty1a
>
> The stty command allows you to set how the end-of-line stuff is
> handled as well, and can be used to automatically supply CRLF.
>

Is there any way to write to it without using echo. In dos, once I ran
"type con>com1", I was able to send data that I typed directly to it. I
guess I could put the strings in a file and use pg or more to send it to
tty2a. However, I would really like to play around with the different
command sequences that it accepts and figure out how to make it do what I
want.

Thanks,
Justin


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Outgoing mail is certified Virus Free.
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In article <bdcvkl$qir$1@news.tdl.com>,
justin <justin_robbs@NO_SPAMhotmail.com> wrote:
>Is there any way to write to it without using echo. In dos, once I ran
>"type con>com1", I was able to send data that I typed directly to it. I
>guess I could put the strings in a file and use pg or more to send it to
>tty2a. However, I would really like to play around with the different
>command sequences that it accepts and figure out how to make it do what I
>want.

Configure the device as a direct uucp device, and then connect to it with cu.
For example, put in /usr/lib/uucp/Devices:

Direct tty2a - 9600 dir

Then:
chown uucp:uucp /dev/tty2a

cu -l tty2a dir

Use ~. at the start of a line to exit cu (probably best to read the cu man page
before you use it).

John
--
John DuBois spcecdt@armory.com KC6QKZ/AE http://www.armory.com/~spcecdt/

In article <bdcp5h$oq5$1@news.tdl.com>,
justin <justin_robbs@NO_SPAMhotmail.com> wrote:
>
>-snip-
>
>> Writing directly to a user's tty device may work, but probably won't on a
>> properly configured system since it has many security implications.
>
>I am just trying to write a string of data to an output only device
>connected via a serial port.
>
>>(how would you like to be running as root and have your F1 key
>>reprogrammed to send ``rm -fr /'')?
>
>That would suck. I have done enough stupid stuff myself without having to
>worry about that.
>
>One time running as root I typed
>l /tmp
>and thought I don't need that stuff so I typed
>rm -fr *
>and walked away to get a drink, unfortunately, local dir was /
>not pretty.

This is why even on SCO systems I change root's home directory
to /root. I just don't think any local directory should be /
anymore.

I've walked into too many places where I got called for help and /
was full of things from user aps, etc.

Making /root the home for root will ensure than an accidental cd
with no arguments will not place you in a dangerous place.


--
Bill Vermillion - bv @ wjv . com

Thanks for all the helpful responses. That got me what I needed. I
appreciate you guys. Have a good day and God Bless.

Justin


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Outgoing mail is certified Virus Free.
Checked by AVG anti-virus system (http://www.grisoft.com).
Version: 6.0.491 / Virus Database: 290 - Release Date: 6/18/03