Very Computer

I want to hook up an old 8088 as a dumb termianl.  I have some serial cable
but it has only four wires so I need to know which pins are essentila for use
and which ones can be ignored.  Also what kindof software do I need to run at both ends.  I was thinking of kermit at the 8088 end, but I have no idea what to do at the linux end.  I need it to send out and receive the login instructions.
any help would be appreciated.  If it would be easier to run minux on the 8088,
please speak up.  I only have a 20 meg drive.  is that enough to run minux.

thanks,
Todd McCoy

: I want to hook up an old 8088 as a dumb termianl.  I have some serial cable
: but it has only four wires so I need to know which pins are essentila for use
: and which ones can be ignored.  Also what kindof software do I need to run at both ends.  I was thinking of kermit at the 8088 end, but I have no idea what to do at the linux end.  I need it to send out and receive the login instructions.
: any help would be appreciated.  If it would be easier to run minux on the 8088,
: please speak up.  I only have a 20 meg drive.  is that enough to run minux.

For RS232 over DB-25, pins 2, 3, and 7 are probably all you
*need*.  2 & 3 are send/recieve.  7 is a ground.  You need a
2/3 swap - as both machines are DCE.  This is what "null modem"
means.

Of course you can get commercial cables that do exactly what
you want at places like CompUSA.  Radio Shack sells generic
straight through cables and all the gender benders & null modem
adapters you could want.

You are running DOS on the 8088?  I used to own a Leading
Edge XT, 8088 at 7.15 MHz & 20 MB hard disk, Dos 3.1.  I
used to connect it to my Mac II, at 19,200 BAUD with kermit
(at both ends).  However, some people have said that "an XT
can only cope with 4800 BAUD, or 9600 on a good day".  Your
mileage may vary.

Kermit generally does not come on Linux distributions (like
InfoMagic).  It can be obtained in source form from
Columbia(?).  It compiled easily for me under Linux.  You
don't need kermit under Linux, but having it on both sides
gives you highly reliably file transfer.  You only need a
modem program on the "terminal" side.

The hard disk is not material.  I used to have a DOS 3.1
bootable floppy with kermit on it.  It had some spare space
for small downloads.  My XT only used 360 KB floppies.
These days I'd add a screen saver, such as scrn (which
just blanks the screen after 15 minutes of dis-use).

There are unix'es that will run on an XT.  Minix and Coherant
come to mind.  I ran Dan Lanciani's OS 88 for awhile.  It
booted in 512K RAM!  I had two logins at one time - one
from the Mac, one on the XT's own console.  Just for fun, I
printed some lables at the same time.  Imagine a UNIX root
file system on a 360 K floppy.

Anyway, running UNIX on your XT will not improve it as
a terminal over DOS, if the sole application desired is
"Dumb terminal".

For that matter, Kermit gives you vt102 emulation, which
is quite a bit smarter than, for example, an ADM 3 dumb
terminal.  Maybe I'm dating myself.

--
Stephen Uitti
Programmer at DCCS, UPENN

Both machines are DTE, that's what "Terminal Equipment" means.

Graham

Has anyone any news about 8088 as a printer server for SMB? (TIA email)

No, minux is a different operating system.

Quote:>We have set up a customer with linux as mail/internet gateway
>in 20MB of disk and 8MB of RAM, so you should be fine.  We could
>get by with 4MB if we weren't running the network stuff.  Not
>knowing what you are conneting to, I can't suggest software,
>but 4-wire should be OK as long as you don't try to push too
>hard (though I have run 9600, and occasionally 19.2K at 150-200
>feet over 3 wires, though there are *no* guarantees as it's
>way past spec!)

Umm, Linux won't run on an 8088...  I'd go for kermit...  We've run
DOS and Kermit on some old "luggable" Compaqs and IBMs with 10 MB hard
drives.

Quote:>For 3 wire, I run both data lines and ground, and jumper
>everything else.  I forget what some of the pins are, but
>on a DB25, I jumper 4 & 5, and 6, 8 & 20.  This is almost
>never what the books say to do, but it works far more than
>anything else I've seen.  You can look up the DB25 pinout
>in any serial reference book...

Look in the serial HOW-TO (http://sunsite.unc.edu/mdw/) for pinouts
and instructions on what to do on the Linux end.

Jason

Why don't you throw away the serial cable, and get one that has RTS/CTS wires.
It will save you a lot of hassle. If you can't (pre-wired building), you should
use XON-XOFF handshaking.

You will also need to find file transfer apps that can live with XON/XOFF.

The PLUS side, is that CTRL-S CTRL-Q on the VDU will pause the screen, without
any help from the application. To be quick try CTRL-M CTRL-S (to catch error
messages).

Graham

        -----------------------------------
        http://www.users.dircon.co.uk/~trix
        -----------------------------------

You could run TELIX which is quite full-featured , it has screen-dump
X-modem , Z-modem , Keybooard mapping - everything you'll need.

If you just want terminal emulation then you could run ANSITERM , it is
very compact and easy to configure. I belive it is free-ware (could be
wrong).
The beuty of Ansiterm is that it will fit on a 360K boot-disk and run
without hard-drive!

The above about cabling is true , but if you can possably lay a different
cable you will get a much more reliable connection.
BEST SOLUTION:

PC-end                  Linux-end
1 ----------shield----  1 (optional)
2 --------------------  3
3 --------------------  2
4 --------------------  5
5 --------------------  4
7 -------SG-----------  7
6,5,8 joined            5,6,8 joined

This will make sure no-one sends when the other end is not ready to recieve.
This cable takes advantage of the -crtscts switch in Linux 's agetty (see
MAN)

If you MUST use 4 wires then do as the previous poster says and use Xon-Xoff
handshaking.

Oh , and don't expect a 4.77MHz XT to cope with anything more than 9600.
A 'Turbo' 8MHz XT might get to 19200 if your lucky.

Have fun!

--
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Really? So what is it?  I know iof minix,
and linux, but what is minux, if not a typo?

-Miles

[7-wire cable solution deleted]

Quote:> This will make sure no-one sends when the other end is not ready to recieve.
> This cable takes advantage of the -crtscts switch in Linux 's agetty (see
> MAN)

Absolutely.  I offered the 4-wire solution only because
he requested it, but you are right, and I should have
said this as well.  He might also simply run DTR/DSR and DCD
through as well.  I've had to do this three times in 15+
years of systems work - to make an IBM3101 terminal talk to
almost anything, to get a 28K modem to run anywhere near 28K
with a usable error rate, and to talk to the async port of
later model Ascend Pipeline 50s.  There are undoubtedly other
times you need more than 3 wires, but these were the only ones
where I have *had* to have them.

That said, more is still safer.

Quote:> If you MUST use 4 wires then do as the previous poster says and use Xon-Xoff
> handshaking.

Oops.  I did leave that out.  <sigh>

Finally, it might be just as cheap and less headaches to simply
check local garage sales, flea markets, and especially ham fests
for cheap used terminals.

-Miles