HP-71 41 Translator module : how to use it ?


Hi, I just received the HP-71 41 Translator module for my HP-71B, but cannot figure how to use it !

When I type "HP41 [END LINE]", it answers "HP41 EMULATOR 1A", and the first time I enter this command it then ask "SIZE (max. 3475 )?". So module seems to be working, but I don't know how to enter in RPN mode and use it as an HP-41C. With the module plugged, I also don't see the ">" prompt anymore, just the full bloc character, and cannot enter in "Calc" mode by pressing "f CALC".
I've almost never used the HP-71B because it didn't had the RPN mode and can only use an RPN calculator. So got this module recenly on eBay, but unfortunately without any manual / instructions.

Does anyone have some tips to start using it in RPN mode ?
Couldn't find documentation on Internet, so if you have an idea on where to get it ?

Thanks, Pierre.


Pierre, After typing "HP41", you must type "KEYS41", and then select the "USER" mode. The HP-71 is now in HP-41 emulator mode. You must know what the keys do; a drawing of the HP-41 overlay is in the back of the "HP-41 Translator PAC Owner's Manual". The MoHPC DVD has the Owner's manual. You must be thoroughly proficient with Sections 1 & 2 of the owner's manual and the normal operations of the HP-41 to use the emulator. Good Luck, John Pierce


If it's just for using the 71B in RPN, you can load or type in the RPNLEX LEX-file. Does a good job. If you don't have HP-IL, you may want to read here how to do that via DUMPLEX and MAKELEX with EMU71.



I've loaded manually the RPNLEX file, and I have now TWO RPN calc on my 71 ! Just tested it a couple of mins, it works fine, maybe faster than the 41 Emulator (or is it just an impression because it doesn't show the operation ?).

If found some functions:

- Pi on P
- RUP & RDN on UP (^) & DOWN (v) key
- Last X on 'f 0' (USER)
- X<>Y on 'f .' (VIEW)
- 1/X on 'f ,' (CALC)
- Y^X on 'f +' (CONT)

But for EXP, SDEV, MEAN : don't see what it does !? Or could it be because i made an error in typing ?!

Is there somewhere a manual of it ? Are some memory/register we can store to, how to change from FIX 4 to ENG 2, ... ???

Anyway, for a daily usage as basic RPN calc, it does it !

Now about this procedure :

If you don't have HP-IL, you may want to read here how to do that via DUMPLEX and MAKELEX with EMU71.

I found it more easy to read if we add/change the following lines, this to have 16 lines at a time, and HEX code in bloc of 4 digits (and this is how I did my very first step in BASIC ;-) !)

50 PRINT @ PRINT @ PRINT "     0123 4567 89AB CDEF  ck" @ PRINT ! Extra spaces in header (one added also before 'ck')
55 C=0 @ INPUT C$ ! Pause before first set of 16 line
70 A$=PEEK$(DTH$(A),16) ! Unchanged
71 A1$=PEEK$(DTH$(A),4)&" "&PEEK$(DTH$(A+4),4)&" "&PEEK$(DTH$(A+8),4) ! Take 4 characters at a time in new string
72 A1$=A1$&" "&PEEK$(DTH$(A+12),4)
80 PRINT DTH$(X)[3]&": "&A1$&" "&FNS$(A$) @ A=A+16 ! Print new string and space added before 'ck'
85 C=C+1 @ IF C=16 THEN C=0 @ INPUT C$ ! Pause each 16 lines
I couldn't add those comments in above thread, I suppose because it is already archived.

MAKELEX program works fine, but typing the 1040 bytes was fastidious (but as least got it). Will investigate a little more how to tranfer via floppy (but must plug all peripherals, ...).


Edited: 27 Nov 2008, 11:22 a.m.


The docs are on the MoHPC DVD. I would strongly recommend reading the docs to leverage the full potential of this must have (IMHO) module.


Many thanks to all of you.

John, the KEYS41 was what I missed to start.
George, will try the RPNLEX as well (too curious for not testing ;-) )
Egan, I have a definitive reason for getting the MoHPC DVD.

In the mean time, I found the HP-41 instructions was recognized, could calculate in RPN mode if I 'Enter' each operation : 2 'EndLine' 5 'EndLine' + 'EndLine' gives 7. Tested also "ARCL X" twice then "AVIEW" showed 77 (continuing above example), RDN, X<>Y, just found "AON" and "$" go in ALPHA mode, ... All this works, and I'm investigating the keyboard rigth now to find other shortcuts.

Now that I can use it in RPN, I will reconsider using it a little more. I've also the HP-IL and FDD 9114B, but not the IL interface on any PC, and I've read some incompatiblity with new laptop FDD, so will try the manual way of loading LEX files (file type I've never heart before).

Resumed, some funny hours in perspective !

Thanks, Pierre.



am I right to assume you do not have the original overlay for the module. I have used the module to do a lot of comparison with my real 41 and without the overlay it is quite difficult (but not impossible).

If you are interested I can at least take a photo and/or copy the overlay, so that you can see where the keys are after "KEYS41".

I am currently also testing the PC HP-IL board together with EMU41 and the 9114B. Without the board it is still possible to transfer LEX files, you just have to follow the procedure mentioned in the great article about HP-IL on this site and some other sources. This transfer works on my old Pentium PC, I am not sure about the laptop although I believe the really critical issue is the OS (no 2000, XP, Vista allowed), not the hardware itself.

If you want to share your experience you are welcome to exchange ideas/findings by email.



John, the KEYS41 was what I missed to start.

Initially I also used KEYS41, but after sometime found it more natural to not use KEYS41 and just spell out what I needed. This also allows you to space delimit stack items. E.g. 3 2 +, instead of 3 ENTER 2 +. I find that I never use the overlay this way.
I've also the HP-IL and FDD 9114B, but not the IL interface on any PC, and I've read some incompatiblity with new laptop FDD, so will try the manual way of loading LEX files (file type I've never heart before).

The incompatibility may also be the OS. You need to use DOS with LIFUTIL.EXE. If you are running Linux you may have no problem with your existing FDD on your laptop, just use the lifutils for Linux.

Language EXtension = LEX

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