Linux is awesome, no doubt about it. Right now I'm in the process of trying to figure out how to network a DEC vt320 terminal to Linux. I think I can do it because I'm certain Linux can do it.
It's like this; vt320 is a seperate terminal (screen), comes with a keyboard, and an external baud modem. I don't need the modem just yet, as I only want to see about connecting from one terminal to the other. The connection is through a six pin
cable the same shape as a phone cord/jack, but the actual connection would have to be through a serial(parallel) port on the Linux box. This is because this terminal came with ModTap adapters, so it looks like;
VTterminal > ModTap > cable > ModTap > Linux-parallel port;
There's a ModTap on either end, terminal side is female, opposite side is male, which would normally be connected to the baud modem. My questions are;
What is absolutely necessary to compile in the kernel concerning this?
Which files should be altered first? I know a limited amount about /etc/terminfo, usr/share/terminfo.
Specifics like, is it necessary to start runlevel gettys from /etc/inittab and/or just configure terminfo? BTW, my inittab has all getty's commented.
Configuring terminfo, this I don't really understand, except /etc/terminfo a-v listings are mostly empty while /usr/share/terminfo contains the features for terminals like vt100's, which this vt320 can emulate.
Basically, I have the terminal side configured (I think) and the cable is connected to Linux, but I've yet to find any activity or sign that Linux knows this terminal is there. I've tried
for port in 0 1 2 3 4 5 6 7; do echo ttyS${port} > /dev/ttyS${port}; done
& shows nothing.
This is about the best source for info I've found, http://www.tldp.org/HOWTO/Text-Terminal-HOWTO.html
I try to follow the Linux-how-to, but this one is somewhat confusing, can anyone help?
Thanks.

To get a VT420 running on Debian Woody....
1.The connection needs a crossover cable. I bought a crossover serial cable. I had to get a small assortment of gender and pin size changers. Whatever you need to plug into each connection. The main thing is the crossover cable.
2. Start a getty in /etc/inittab for the serial line you will connect to. This is the example from Debian:
# Example how to put a getty on a serial line (for a terminal)
#T0:23:respawn:/sbin/getty -L ttyS0 9600 vt100
#T1:23:respawn:/sbin/getty -L ttyS1 9600 vt100
3. It is possible you may need to correct a setting on the terminal setup screen. By default I needed to make a change to the xoff setting on the terminal.

If the connection is correct, a couple taps will bring up a login prompt.

Yeah, just add those getty lines for ttySx, and you should be set. When I setup my VT420, all I had to do was uncomment the serial console lines in inittab, and plug it in.

If you are talking about the same cable that my VT420 had, it looks exactly like a phone cord, but the tab is off to one side? If so, I use and adapter that converts that to a female DB9 (standard serial port). Works great, you should be able to pick one up from BlackBox.

Interesting. I've not gotten it working yet but I thought it was possible.
I've gotten the kernel ready on parallel/serial support.
The terminal is set towards vt100 emulation & the getty lines are set.
I'm glad those inittab lines were mentioned because that was a big part of my confusion;

etc/inittab
# /sbin/getty invocations for the runlevels.
# The "id" field MUST be the same as the last
# characters of the device (after "tty").
# Format:
### I'll try with 2 & 5.
# <id>:<runlevels>:<action>:<process>
#1:12345:respawn:/sbin/getty 38400 tty1
2:2345:respawn:/sbin/getty 38400 tty2
#3:2345:respawn:/sbin/getty 38400 tty3
#4:2345:respawn:/sbin/getty 38400 tty4
5:2345:respawn:/sbin/getty 38400 tty5
#6:2345:respawn:/sbin/getty 38400 tty6
# Example how to put a getty on a serial line (for a terminal)
### I'll try both.
T0:23:respawn:/sbin/getty -L ttyS0 9600 vt100
T1:23:respawn:/sbin/getty -L ttyS1 9600 vt100

I've read that >setserial can be a deciding factor with this style networking
but for now I'll experiment with inittab.
Concerning the crossover cable, these ModTaps look like this male side;
0, no pin: 1, pin
1-13= 0111111100000
14-25= 000000101000
I'm alsmost certain this qualifies as a null modem/cross over cable, but I might be way off about it. The vt420 and vt320 are close, this also has the tab off center.
There are multiple slots with the tab like this, one for the printer, keyboard,
one for this adapter connection, and one for something else. That one has an icon with
two arrows going in opposite directions, maybe if the adapter doesn't allow from the term's Comm port I could try this other port without the adapter(the Linux end still connected by modtap).
This is an interesting project. I appreciate the input .

Your first post mentions attempting to connect to the parallel port on your Linux box. AFAIK this is wrong. The VT should connect to the serial. The connections on a VT a confusing. The first one I worked with had a parallel size port as the primary serial connection. This is the one I needed adaptors for. I have also seen only phone jack type connections for both serial lines. There is a printer connection thrown in also.
Here is a good site for specs on the terminal:
http://vt100.net/

I see, finally. I kept thinking, square peg, round hole.
The ModTap is totally wrong for this, I need a serial adapter, or a different
style connection cable altogether. Confusing they are. This VT still
runs strong even though it's rapidly approaching 20 years off the shelf.
Thank you for the help.

Hello!! I have a big problem with my vt420.

I have a VT420 Terminal connected to a Acer tm634 laptop trough an usb-to-serial converter (pl-2303)
and an rs-232 cable.

The laptop runs Debian Sarge.

this is in my /etc/inittab file:

USB1:23:respawn:/sbin/getty -L ttyUSB1 9600 vt420

I got the login prompt working, and i also manage to log in,
but the problem is that only the first line of the screen is used!!

When i hit the Return-key the cursor only jumps to the beginning of the first line, and not to the next line.
in my opinion there's only a CR echoed back from the laptop, and no Linefeed LF!

A login looks like this:

Login: username

I hit the return key... but the cursor only jumps to the beginning of the same line and writes over the text there:

Password: rname

i can write my password over the rest of "username" and login, but in the shell i get i also have no way of creating a linefeed with the return key.

Btw
I had the same terminal running with a pentium pc and debian some years ago, and it was working without problems.

How can i fix this?

Since you do not specifically say, I will ask, is the serial cable a crossover cable or straight through?

thank you for your quick answer!

I'm using this cable set from hama:

- 1 x connection cable 9pin. D-jack - 9pin. D-jack
(with crossed wiring)
- 2 x adapter 9pin. D-plug - 25pin. D-jack

www.hama.de/portal/articleId*21461/action*2563?lid=2#4

and this USB to rs232 converter:

www.intolan.com/PhotoGallery.asp?ProductCode=GEN%2DUSB%2DSERIAL&PhotoNumber=2#largerphoto

but i use only one 9pin-25pin adapter (at the terminal side), because the usb2serial converter is already 9pin.

i dont really think that the cable is the problem as i do get a login prompt (from time to time),
the problem is that there are no newlines...

thanks

Looks like the cable is entirely correct.
I would go into troubleshooting mode then.
I think I would try hooking the terminal to a PC that didn't need the USB/serial converter to see if the problem still persisted.
If it did I would check the VT settings.
You could also possibly try a PC to PC serial connection (using the USB/serial converter or not) to confirm or eliminate a problem with the VT settings.
Sorry I don't have a better answer.

Thank you.

Anyone else got this problem with newlines on a vt420??