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It's a black box. Approx 9 cm (3.5 in) x 14.5 cm (5.8 in) x 3 cm (1.2 in).

In large embossed letters on one side (top?) it has CMT.

On the other side (bottom?) it has a label reading: CMT Corvallis Microtechnology, inc. Model# RD512-01 Made in USA Serial# 744163 Complies with the limits for Class B...

It has a battery compartment which holds a 9v battery and a lithium cell.

It has a power jack. and an HPIL interface with 30 cm leads (i.e. *not* sockets on the box) on one end.

The other end has a 9 pin male D connector, 2 recessed push buttons (labelled On and Off and 2 LED indicators labelled on (yellow) and Bat (red).

Some things that won't help you identify it, but are kinda interesting include labels:

"Jacquie - New lithium and 9v battery fitted 16/9/94"

"Wilson wheat"

"datrec datdump ldev lsel primemp rpl rsys..."

The unit has 3 *very thin* pc boards with chips mounted both sides of other boards. It has an NEC V20 chip.

It was *probably* used with HP71's.

So what is it?

Maybe you can give us pictures... This would be much more easier....

These units were used as temporary mass storage by data collectors

Yeah, I expected as much. The full kit used by these people appeared to be a 71b (with *lots* of memory), a cassette drive, a printer and one of these.

I really don't know what they used them for, but it was something to do with wheat!

I'd be really interested in further information about this mystery box -- does it have a name for instance? (I don't think they were called Jacquie :-)

I'll try to arrange a picture later today. It may have to come from my scanner though.

What do you mean, *lots* of memory ?

The item is a CMT "Ram Disk" which mimics a HP-IL tape drive with NO moving parts. Yours also serves as a RS-232 interface. You have the top-of-the-line unit. Congratulations!!

The RD512 should appear as four separate HP-IL devices as each 128K block of memory would be a separate device. The RS-232 would appear as a different device. There is a way to configure the unit as one contingous 512K block. I'm unfamilar with this.

I have the 128K unit (RD128) without the RS-232 functionality. I use it as I would a tape or disk drive. I've owned mine for about 18 yrs with no problems.

I still have the manual for mine. I could scan some pages for you if you require them. It might take a day or so to find the right box. The manuals for the 82161A tape drive and 82164A RS-232 interface should get you started. All of the mass storage commands associated with the HP-IL, EXT I/O, and the mass storage/duplication ROM work. Commands associated with the DEVL ROM can provide unexpected results.

The required lithium cell (so you don't lose memory when you change batteries) is a CR2325. I get mine here in the US from Radio Shack (part # 23-169)


Why must you steal my name? Use a comma or something *g*


all were either chokka with 32K ram modules or had a 128K module.

In those days that was a *lot* of memory.

Steal your name?


This is the earliest post I can find on this site that I made (not that I looked too hard)


(Which reminds me -- I must finish that off one day)

Steve :-)

Sorry, I mean there are at least 2 people posting with a name of ".", which I was using first!


Well, one of us is :-D

Yeah, I'd be *very* keen to get hold of some documentation.

I suppose the related question is "What happened to CMT and has there been any effort to get them to release to Dave copyright permission to include their documentation in his CDs?"

But Lawence, expect an email soon with my contact details. :-)



you related that inside there is an equivalent
processor......from hp developped in the past
.......yes in most different computers and pocket computers from hp but for an interface i m
in doubt,,....using a really good computer processor
to do the job...... why not a microcontroller or a speciallized chip...... i agree to Mattias.
Let s have a look on a picture to check
the point of VIEW (to see).
in corvallis hp develloped most of laptops..

regards from EEC.

Steve wrote:

I suppose the related question is "What happened to CMT and has there been any effort to get them to release to Dave copyright permission to include their documentation in his CDs?"

They are still going strong, see www.cmtinc.com

They moved from using HP handhelds to making
their own (the Marys family), and now they
provide solutions using WinCE units and other
hand computers.

When I visited a few years ago to talk to the
boss he said it was not commercially worth
his time to deal with old stuff. Maybe someone
in or near Corvallis would like to go ask him
specifically for permission to make the manuals