12 Apr
2005
12 Apr
'05
11:03 a.m.
On Apr 12, 2005 9:47 AM, Jay West <jwest at classiccmp.org> wrote:
Yeah, I guess you're probably right there. In that
case, perhaps someone can
guide me. I've seen scads of HP models on ebay. However, often the
description isn't clear enough to determine if the unit just supports sync,
or just async, or just X.25, etc. etc. Having a penchant for HP gear (have
you noticed?hehe), does anyone know what model of HP protocol analyzer is
the right one for RS232, sync & async? Some of the ones I've seen there
APPEAR to be very specific for things I wouldn't want and I'm just not up on
the HP models of this.
The 4951A and 4951B use TU58-style data carts (down to the capstan
turning to goo). Unlike a DEC TU58, the HPs format blank tapes. The
4951C uses a 3.5" floppy. Beyond that, there are different 'pods' for
the physical layer. All of them attach to the analyzer in the back
and provide some sort of traffic light functionality, plus a suitable
physical connection (DB25, DC37...) for the physical standard in
question. I have one RS-422 pod, and one RS-232 pod, and I forget
what the 4951C pod is, but probably RS-232.
Presuming one has a 495X with DB25 RS-232 pod, all of the models I
have do sync and async just fine, ASCII and EBCDIC, have the internal
programming language which can trigger captures on in-band data, etc.
The 4951C has an optional terminal (VT100) app that is on a copy
protected floppy, and I don't know if it's possible to buy it from HP
anymore. Obviously, with capture media being the way it is, I'd
recommend a floppy-based HP if you need to save sessions. If you
don't care, and won't be doing extensive protocol programming, even
the tape-based ones are great.
All I can say is that my experiences with this line of protocol
analyzer have been great, and if you are snooping non-exotic
connections, probably any of them will work fine. If you have some
bizarro need, you might want to google up particular models as you see
them appear on eBay (item 7506826828 has a good picture of a 4952A, as
an example.) Prices sure do seem to vary. Glad I already have a few
working ones. The non-working ones go cheap, but I have never had to
fix one, beyond the mandatory gooey capstan replacement.
-ethan