HP UX 11i. RS232 comms Null Modem issues

[John O'Neill_6]

Hi,

I'll quickly explain my situation and query in the hope that someone reading this can shed some light on what we need to do to resolve this issue.

In our production environment, our primary server uses a MUX adaptor (with a 16port mux board that has lots of DB25 connectors on it). One of these ports has been confiured as a 'modem' to allow direct connection to another computer via RS232 for the transmission of transactions from one system to the other.

Our system is a HP UX 11i, their system is a windows system.

We have a script which starts the background process that deals with the transactions and another script that configures the comms port, here is the script.

# Configure comms device
stty min 1 raw 9600 -echo evenp istrip stty min 1 raw 9600 -echo evenp istrip
This is working absolutely fine in production, they have their set up as:
Network=Async
Port=COM1
Parity=Even
Speed=9600
DataBits=7

Works fine, 24 x 7 and all is happy...

Now onto my problem.

As part of business continuity, i need to have a replicate system that can 'cut in' if something goes pear shaped at our main processing site.

We've got another HP UX machine ('L' Class) with a MUX card (the one that has the fly cable with 6 ends on it) connected to a
system that is identically configured to the one at our primary site.

We've set the device up the same way in SAM, done the same things (device name is different though) but... our config script just pauses.

Here's the config script:

# Configure comms device
stty min 1 raw 9600 -echo evenp istrip stty min 1 raw 9600 -echo evenp istrip
Now... the script just hangs, you can sit there for a very long time and eventually you see the following...

./fdr_stty[5]: /dev/cua2a6: cannot open
./fdr_stty[5]: /dev/cul2a6: cannot open

I've run emux_stty and it can see the port there.

I've checked permissions on the /dev/cua2a6 and /dev/cul2a6 files and they match the production system.

I've been told that the issue could be a bad cable, wrong pinout connection, all sorts of things.

I guess my main question is this...

A) Shouldn't the 'stty' command succeed regardless of whether there was anything connected to the port or not? It is after all just configuring the paramters that we'll be using, it's not actually making a connection to another system.

B) What's the best way to see if the MUX card itself is working properly?

I can't find anything in syslog.log or anywhere else indicating a hardware failure, SAM seems happpy to configure the device...

In our productione environment this was a trivial excercise, but for my DR system it's becomming a major problem, unless i can get this comms issue resolved the my DR system isn't where i want it to be.

Any help appreciated, happy to supply more information if needed.

-John