Subject: Re: hooking up a console
To: bart sikkes <b.sikkes@gmail.com>
From: todd <markleyt@compusleuth.com>
List: port-vax
Date: 02/18/2007 00:00:35
Bart:
          The serial port settings all look good, but the 9600 speed may 
not match the computer. The quotes "bunch of non logical characters" and 
"repeating a similar block" could be a symptom of mismatched baud rates. 
You may try different baud rates. The baud rate on the uVax II, and uVax 
III were set using jumpers or switches on the console device plugged 
into the CPU board. I am not sure how it was set on the models you 
listed, but 9600 and 19200 were common defaults.

         Without documentation on each device I can't answer your cable 
connection questions, but most serial connectors have two different 
types "DTE" and "DCE", (Data Terminal Equipment & Data Computer 
Equipment). The main difference between them in this situation is which 
pin in the connector is output, and which is input. The two types have 
opposite connections for input and output so they can be connected 
directly to each other, pin for pin, with a "straight through" cable. If 
you need to connect DTE to DTE, or DCE to DCE, then a "null modem" or 
"flip cable" would be required, connecting each input to the others 
output. Each manufacturer used different standards for which of these 
two, DTE/DCE, were put on terminals, and computers. The type of 
connector also changed over time including DB25, DB9, RJ45, RJ12, and 
DEC had a custom RJ45 like connector with an off-center clip. The two 
standards, DTE/DCE,  for pin connections on the DB25 are well known, but 
some of the others depended on the manufacturer.  Fitting the cables and 
connectors will only work if the correct pins are interconnected, 
matching the inputs with the outputs. You also need a common ground 
connection between the two ends for a minimum of 3 wires. These serial 
connection problems were often solved using a tool called a Breakout 
Box. Other ways included using a volt/ohm meter, scope, or just using 
trial & error. You should find an idle output between -5 and -12 volts, 
the break will set between +5 and +12. Input pins are often less then 3 
volts or close to zero.  The important pins in the DB25 are:

1 - Frame_Ground
2 - Input or Output
3 - Output or Input
7 - Signal_Ground

Todd

bart sikkes wrote:
> hello,
>
> this isn't really related to the vax port itself, but this is the best
> place i can find for asking vax related questions. if there is another
> place that would be better please let me know.
>
> i got a couple of vax boxes and eventually i want them to run netbsd.
> but currently im mainly interested in checking their status. for that
> i believe that hooking up a console would be the easiest thing to do.
> i got a couple of terminals around here that should work i guess, but
> im unable to make this work.
>
> i got a VAXstation 4000 VLC, a VAXstation 4000 60 and a MicroVax
> 3100-30. for terminals i have a Texas Instruments Model 928 VDT and a
> Wyse WY-50. in my mind i should be able to just hook up a console to
> the correct port on the vax and i should get output. but is it indeed
> that simple? could in general a TI terminal be used or do i need vax
> terminal or such?
>
> i have a cable with two phone like connectors, i believe these are
> used in the DEC423 ports? all the vaxes have one or more of the port
> these connectors fit into and the TI terminal has it also. making this
> connection seems like the logical thing to do, but is it the correct
> one?
>
> with an uVax II i once worked on i used a serial DB25 female - female
> DB9 cable, but i think i need a serial DB25 female - DB25 female cable
> for these vaxes and terminals. can any basic female-female DB25 cable
> be used for this and would it work better or differently from the
> phone connectors like cable?
>
> currently when i hook up any of the three vaxes to the TI terminal i
> basicly get either a bunch of non logical characters or nothing. with
> the 4000 VLC it keeps repeating a similar block of characters on
> screen. with the 4000 60 i see nothing on the screen, but that one has
> a bunch of such DEC423 ports, so perhaps i have the wrong one. the
> 3100 shows a couple of weird characters after boot and remains at
> that.
>
> from some googling i found that you can set different things on a
> terminal. the TI terminal has a large menu with many options and i
> tried to set them to what i felt was correct, but im unsure if this is
> correct or if these settings can cause the weird output.
>
> the vax is connected on port 1 and these are the settings for port 1
> on the TI terminal
> communication: half duplex
> data length: 8 bits
> parity: none
> stop bits: 1
> xmit baud: 9600
> recv baud: =Xmit
> xmit pace: Xon/Xoff
> recv pace: DTR/Xon/Xoff
> limited transmit: off
> dsri: no
> cts: ignore
> cd: ignore
> break duration: 170 ms
> disconntect delay: 2 sec
> aux printer type: national
>
> are this correct settings for a connection with a vax? or does it
> differ per vax? and can the other terminal settings influence this
> behaviour, the emulation settings or such?
>
> i know this is perhaps what a basic / vague question, but i got little
> to no experience with terminals and such (i started with personal
> computers, not this type of machines) and i would like some guidance.
> what are common problems i can check in this setup, perhaps its
> something rather silly i just don't know how to do.
>
> thanks in advance,
> bart
>