HP-71B HP-IL module question


I found something strange in the HP-71B HP-IL module manual on the MoHPC DVD. In this edition January 1985 of the manual, on page 241, two error messages are mentionned (255021 "Low Battery" and 255029 "Medium protected") that are not in my own manual (edition of January 1984):

The most intriguing thing is that none of my various HP-IL modules have these error messages.

That's why I would like to do a small survey inside the HP-71B owner community:

can you try MSG$(255021) and MSG$(255029) and check if you get a message? You will need a LEX with the MSG$ keyword (for instance the Forth or text editor modules have it). Make sure the JPC LEX is not installed, since this LEX redefines the HP-IL messages.

I would be very interested to know if an updated HP-IL module did exist.

Thanks J-F


MSG$(255021) and MSG$(255029) both return an empty string on my HP71:1BBBB HPIL:1A.

MSG$(255022) returns "File Not Found".

Mark Hardman


I second that.
Also for my HP71:2CDCC HPIL:1B



HI, J-F.

First of all, thanks for sharing this news. I would like to know if it is possible to add the serial # of the updated module as well. Chances are identification may also occur this way, what do you think?

I have an HP71B with IL module, it is without batteries for some time. It was failing the last time I used it, but a quick check up led me to clean the interconnector between the two circuit boards. I'll have to recollect my knowledge about creating a LEX file... It's been a while and I did it only two times by following a recipe (I actually only had the chance to put my hands in an HP71B after I was about 40 Y.O., thanks to the good Doc. Meyers). Any link with directions so I can do it quickly? Shameful thanks...


Luiz (Brazil)


For one of my 71Bs I get nothing for these two code however on the other for 255021 I do get "Low Battery" and for 255029 I get "Write Protected". Both HPIL modules are the 1B version the one with no messages is serial 8745 the one with the messages is 8909.


Perhaps it could be interesting to dump those modules ?

I'm interested for my HP71b emulator on android.

Btw, rom image for hp41 modules are everywhere, but for hp71 modules, there is no images outside math, forth and hpil. Could something can be done ?



Since several EPROM modules (mostly for the card reader slot) were built for the 71, one can assume that the required ROM images were also available by those days.

I've collected several of them along the years. I don't have them with me at the moment though, will try to find them as I get back home.

I remember some users here were interested when I got the "HP-71 Demo ROM" image... :-)

However, a lot of specific (corporative) application modules were also built for the 71, and these are not as easy to find.

Will keep in contact.



Hi Paul, are you sure you don't have JPC LEX installed in the 2nd machine?

JPC LEX re-defines HP-IL messages and 255029 is changed by JPC LEX to "Write Protected", whereas the HP manual states "Medium Protect".


Good catch, yes I do have the 32K version on a card reader port module and when I remove it, like my other 71B and everyone else I get nothing for those two message numbers.


If you don't have the MSG$ keyword and not easy way to load a LEX with it, you can replace MSG$(255021) and MSG$(255029) by

POKE "2F7E4","51FF" @ ERRM$ and POKE "2F7E4","D1FF" @ ERRM$.


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