Half-duplex VT420?

From: Iggy Drougge <optimus_at_canit.se>
Date: Mon Oct 8 22:43:04 2001

Dave McGuire skrev:

>On October 9, Iggy Drougge wrote:
>> Since I'll be running another headless computer (HP 9000/380), I brought
>> home my VT420. Nice terminal, but unfortunately this specimen will only
>> talk, not listen. At first, I suspected my HP had lost its settings (the
>> stupid boot PROM must be set via the keyboard to use a serial console). I
>> proceeded to bring my HIL keyboard home and set it (without any screen) to
>> use a "remote" console again, and the machine seemed to acknowledge that,
>> beeping happily. But no response from the terminal. So I tested it with my
>> DECstation. No response there either. So I hooked it up to my Amiga. Typing
>> at the keyboard, there was output in NComm, but doing the opposite didn't
>> work at all. So we have only one-way communication. What could be the
>> problem?

> Is flow control enabled on the terminal? I assume you're using a
>DB25 adapter at the other end of an MMJ cable. Try turning off flow
>control in the communications setup menu and shorting pins 2-3 on the
>connector. At that point the terminal should echo what you type back
>to the display. If it doesn't, you might have a toasty RS232 line
>receiver in your terminal.

Actually, my VT420 is equipped with a DB25 port. I haven't tried the MMJ port
yet due to my currently frosty relations visavis that interface (I spent a lot
of effort soldering a twisted cable a while ago for connecting to a MicroVAX,
then it turned out that I had un- twisted the cable instead! =).
There is no option in my setup (version 1.3) for turning off flow control,
it's either XON/XOFF (two different intervals) or modem control (RTS/CTS?).
Modem control doesn't work. Either the cable I'm using right now is a three-
wire one or the VT has lost the ability to sense those signals, since it will
just "wait" if that option is activated.
I've used the HP box with another VT420, which worked fine. But this VT has
disagreed with three systems now.
I'll try the loopback trick, though.

But if I have a toasted line driver, wouldn't that strike both inbound and
outbound data?

En ligne avec Thor 2.6a.
When cherry tree blooms, people go and walk there, eat dumpling, bring sake
and talk each other such things as "A superb view!" and "Full of spring here",
and they become very happily and cheerful. But this is a lie. People gather
below cherry trees and get drunk, vomit, fight, which are happening since the
old days of Edo period. From long time ago.
Received on Mon Oct 08 2001 - 22:43:04 BST

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