75C and 41C!


Just for the fun, i plug my newly acquired HP-IL module from my HP-41C to my dislike HP-75C; so still for the fun, can i "hadshake" them or send something from one to the other? A friend of mine told me to plug it in my HP-71B but i can't find the IL connectors on my 71B; is it integrated like my 75C or an option card like my 41C.

Same question for the card reader : on my 75C i found the card reader but no traction was made on my cards; what is the command for reading the cards? Where is the card reader on a 71B an option too???

Thanks again

An HP beginner...


Hi Michel,

I can't respond to all your questions but here are the few I know the answers to:

71B HP-IL is provided by an optional module. There are several for sale on eBay at this time. I just bought two myself. (I only needed one, but the one sure way to get what you want on eBay is to bid for two identical items at the lowest price imaginable; Murphy's law says you're sure to win both, and if you only bid the insanely highest price for one, Murphy says you'll certainly lose it in the last 9 seconds to a sniper)

75C built-in card reader as well as 71B card reader (option) is a manual pull-through type. There is a command to read/write etc, but you must pull the card through by human power. The computer will prompt you when it is time to pull the card.

I also would like to know if there is an HP-IL way to make a 41C series talk to a 75C and a 71B.



I would also like to connect my 41CX with my 71B, I have HP-IL interfaces for both but have not worked out the software required (not enough time to work through the manuals and try things out).

Help with some software for this would be welcome from anyone...

I am not sure why I want to make them talk but it would be fun and interesting, and might stop them feeling lonely!


Or how about some software to get 2 71B's ot 2 41C's to talk to each other?

I have 2 of each...


A few things to know: To make 2 (or more) HPIL units communicate, one must be controller, and the other(s) are devices. HP41 and HP75 are always loop controller, HP71 can act as controller or device.

It's very easy to make 2 HP71 talk to each other:
just make RESET HPIL then RESTOREIO on the first one to take control of the loop, then you can do (for example): COPY anyfile TO :HP71 from the first one, and COPY :LOOP from the second one!

There is no easy way to make 2 HP41 talk to each other. You need either special complex software (using IL dev module for example), or 2 interfaces (GPIO, RS232) connected back to back.

In the case of one HP41 and one HP71, do CONTROL OFF on the HP71, then you can do OUTA on the 41, and ENTER :LOOP;A$ on the 71B (only an example!)

HP75 <-> HP71: it's similar to 41 <-> 71, just make 71 give control off.

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