VT420 Console - a quick question

Discussion:

(too old to reply)

Tomasz Dryjanski

2005-07-21 12:15:56 UTC

Hi All,

I'm trying to deploy an Alpha Server 1000, 4/266. I've connected
a VT420 terminal via the DEC-423 port, and I've set the config
as recommended, i.e. Transmit=Receive=9600, 8 Bits No Parity,
1 Stop Bit, etc. Instead of the startup messages, I can see some
garbage like
p~~~~~~~~p~x~~|~~~~~~~~~~'~~|~~ etc.

I've tried several different settings, with various types of garbage
as the result (some of it contained reversed '?', some contained
mainly umlauts), but this is not what I'd like.

Can you please advise? Alas, I need a quick solution...

Regards,
Tomasz

d***@snowy.net.au

2005-07-21 13:31:29 UTC

Permalink

Post by Tomasz Dryjanski
Hi All,
I'm trying to deploy an Alpha Server 1000, 4/266. I've connected
a VT420 terminal via the DEC-423 port, and I've set the config
as recommended, i.e. Transmit=Receive=9600, 8 Bits No Parity,
1 Stop Bit, etc. Instead of the startup messages, I can see some
garbage like
p~~~~~~~~p~x~~|~~~~~~~~~~'~~|~~ etc.
I've tried several different settings, with various types of garbage
as the result (some of it contained reversed '?', some contained
mainly umlauts), but this is not what I'd like.
Can you please advise? Alas, I need a quick solution...
Regards,
Tomasz

keep reducing the speed?
phil

j***@ccs4vms.com

2005-07-21 14:31:29 UTC

Permalink

Are you sure you are on the correct port on the back of the VT420? Try
the other port.

In global settings, make sure that one or both ports are set to a
session, not a printer (mine are usually set to "S1=Comm1,S2=Comm2",
and each session is connected to a system. Then make sure you are in
the correct session for the port you are using when you set the
communication parameters. F4 toggles session 1 and session 2, F3 setup
gets you to the communications settings for the port on the session you
are currently in.

Your settings should be correct if the console settings haven't been
changed. I once got stuck working on a VAX that had its console set to
7,E,1, which produced some ugly displays on a default mode terminal; I
can't recall if an Alpha could be similarly set up.

Rich Jordan

j***@ccs4vms.com

2005-07-21 18:31:15 UTC

Permalink

One other thing you can do to verify operation of the terminal and its
ports, and your cable. I love VT420s for this!

In global settings, have the ports set as above to "S1=Comm1,S2=Comm2".

In _each_ session (use F4 to switch) set the comm parameters where you
want them (9600,N,8.1 is good) making sure both ports are set the same.
Also make sure the terminal is online in the setup.

Connect the cable from one port to the other. Type something in the
session you are in. It probably won't echo unless you have local echo
turned on for some reason.

The session icon in the lower left corner should reverse to show the
'other' session has data. Hit F4 and you should see what you typed.
Now type something different, and again you probably won't see it, but
again the session icon should reverse. Hit F4 to return to the
original session and you should see what you just typed. If so, ports
are good, cable is good (or good enough), and terminal is working
acceptably. If not, then you need to do some more research.

Rich

Kevin Handy

2005-07-21 16:44:45 UTC

Permalink

1. Bad/wrong cable. Is your cable wired backwards?
There are two ways to build a MMJ cable. One is
null, and one is straight-through. Hold the two cable
ends side-by-side, and compare the colors. If they
go across in the same order, it is the wrong cable.
If the go across in reverse order, it is the right
cable.

Also a bad ground, and sometimes even a broken
transmit/receive wire, can cause really strange
problems like this.

2. Wrong baud rate. Try other common speeds
(19200, 9600, 4800, 2400, 1200, 300)

3. Bad VT420. Does this terminal work on other
computers? I've seen ones with bad serial ports
before.

4. Bad console port.

...

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JF Mezei

2005-07-21 17:44:06 UTC

Permalink

Post by Tomasz Dryjanski
1 Stop Bit, etc. Instead of the startup messages, I can see some
garbage like
p~~~~~~~~p~x~~|~~~~~~~~~~'~~|~~ etc.

The above is indicative of a wrong serial line speed.

What you need to also look is whether this all comes in one burst, of it it
comes in myultiple small group of junk. When you power up, messages appear in
small group of characters.

Also, you need to consider that if the terminal is not set at the right speed,
its sampling rate will be different.
For instance, if the computer is transmitting at 110 baud, but the terminal is
set at 19.2k baud, then each character sent to the terminal will be sent over
a period of time where the tertminal will expect to see roughly 175 characters.

So the length of the bursts of "junk" can indicate if your terminal speed is
higher or lower than that of the computer.

If the data appears more or less ok, but every second characters is screwed
up, with accented and weird characters abound, then it is a 7/8 bit and parity
issue.

Not sure about the 420 per say, but with older terminals, after changing speed
of the port, once had to use the "init comms" menu option for it to take effect.

Mark Schuster

2005-07-24 23:10:56 UTC

Permalink

Did you also set the "console" parameter to serial?

Post by Tomasz Dryjanski

Set Console Serial
Init

If the console parameter is set "graphics" then it expects to have a
DECwindows terminal.

David J Dachtera

2005-07-25 01:01:15 UTC

Permalink

Post by Mark Schuster

Did you also set the "console" parameter to serial?

Post by Tomasz Dryjanski

Set Console Serial
Init

If the console parameter is set "graphics" then it expects to have a
DECwindows terminal.

Oopsie! DECwindows doesn't run on the console, and is optional once VMS
boots.

You meant to say that "it" (the Alpha) expects to communicate via the
keyboard port (for input) and the video display card (if present)(for
output).
--
David J Dachtera
dba DJE Systems
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Tomasz Dryjanski

2005-07-25 06:16:44 UTC

Permalink

Some facts:
- I believe the port is OK, since the server used to work with
an Equinox not a long time ago. The speed was then 9600.
- The cable also should be good, we used to use it for the purpose
- Yes, the terminal may be faulty. Sometimes when powered on
it says "NVR Error". We'll try another.

Many thanks indeed for your hints.
T. D.