serial line monitor suggestions (HP 4951?)

[Chris Campbell]

I need to be able to look at the bits/bytes going back and forth on a
serial line. I don't really need to *emulate* anything in particular,
like *be* the DTE or DCE, I just want to sniff the line that two other
devices are talking on so I can troubleshoot. Besides RS232, I need
it to do 422 and maybe 485 (e.g. address filtering). This is for
pretty low speeds -- 38400 max and I could even live with just 19200.

The PC-based tool I'm using now just suuuuuucks. At a previous job we
had a small standalone HP analyzer which was extremely useful;
naturally I don't remember the model name but googling around leads me
to think it was an HP 4951x. That model apparently has some storage
capabilities -- I don't need that either (just a RAM capture is fine).

Can anyone suggest similar analyzers for this purpose? No SONET, no
STP/UTP, just plain old low speed serial lines ... Once I have some
models identified then I'll start looking for used units.

Thanks!

 

[[email protected]]

I need to be able to look at the bits/bytes going back and forth on a
serial line.

This might be the PC-based tool you are using, but: see
http://groups.google.com/[email protected]&output=gplain .
The blurb is still there; if the code isn't still there let me know
and I will mail it to you. A couple of outboard converters will
let you do 422 and 485. The code doesn't have address filtering but
you could probably add it - you'll need a DOS C++ compiler.

Matt Roberds

 

[Chris Campbell]

This might be the PC-based tool you are using, but: see

http://groups.google.com/[email protected]&output=gplain .
The blurb is still there; if the code isn't still there let me know
and I will mail it to you. A couple of outboard converters will
let you do 422 and 485.

Thanks for the response. I really don't want to go with a PC-based
solution, as I've been down that road and I know where it ends I
want something standalone that doesn't require a PC and doesn't
require conversion. I need to look directly at the 422/485 lines and
that means no PC and no line conversion.

Is an HP4951 going to do this for me?

 

[[email protected]]

I really don't want to go with a PC-based solution, as I've been down
that road and I know where it ends

At one job, we had an ancient HP serial analyzer and a PC-based one
on a laptop. The laptop one didn't work at first, and the HP, despite
being ~25 years old at the time, worked fine. I finally futzed with
drivers and reinstalls on the laptop for about half a day and got it
working well, because I needed to go faster than the 9600 bps the HP
could do. So I understand what you're saying.

I don't remember the model of that analyzer, but it was from the mid
70s or so. It had a CRT and about a 20-key keypad on the front, not
a keyboard. Above the screen, there was a matrix of holes that you
would plug gold-plated pins into to set which lines it was monitoring,
how the modem control lines worked, etc.

At another job, I used an HP analyzer that was newer - it could store
data on a 3.5" 720K? floppy. Pictures from Google (below) tell me
that this analyzer was probably newer than a 4951, while the one I
talked about above was older.

Is an HP4951 going to do this for me?

I don't know if you found this already, but
http://www.classiccmp.org/pipermail/cctech/2002-September/002207.html
has a link to a scanned HP ad at
http://www.helmut-singer.de/pdf/hp4951c-4952a-4954a-4955a-4972a.pdf ,
which says the 4951C does 232C and 422A. No mention of 485. Googling
on "hp 4951a" and "hp 4951b" also produces useful results, with
specifications and a few mentions of units for sale.

Matt Roberds

 

[Chris Campbell]

Thanks for the excellent links -- this gives me a foothold to start searching with!

 

[[email protected]]

I need to be able to look at the bits/bytes going back and forth on a
serial line. I don't really need to *emulate* anything in particular,
like *be* the DTE or DCE, I just want to sniff the line that two other
devices are talking on so I can troubleshoot. Besides RS232, I need
it to do 422 and maybe 485 (e.g. address filtering). This is for
pretty low speeds -- 38400 max and I could even live with just 19200.

The PC-based tool I'm using now just suuuuuucks. At a previous job we
had a small standalone HP analyzer which was extremely useful;
naturally I don't remember the model name but googling around leads me
to think it was an HP 4951x. That model apparently has some storage
capabilities -- I don't need that either (just a RAM capture is fine).

Can anyone suggest similar analyzers for this purpose? No SONET, no
STP/UTP, just plain old low speed serial lines ... Once I have some
models identified then I'll start looking for used units.

Thanks!

Try the good ol' HP 4952A with the pod for RS-232 and RS-422. There are
many pods available (for ISDN too) but I don't remember anything about
RS-485.
Regards
Franco

 

[Thomas Lutz]

There is a free tool called TALBreakout avbailable at the following
URL that should do what you require quite nicely.
http://www.taltech.com/freesoftware/fs_sw.htm

Download the TALBreakout program and read the help file to see how it
works. Basically it is designe to run in a PC with two serial ports
where you connect the PC in between another PC and a device - i.e.
like a breakout box. It then displays everything that goes through the
serial line in both directions.