Posts: 408
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Joined: Oct 2007
Hello Luis,
that's not an HP7470A which is a 2-pen plotter, can be used with an HP-41C with HP-IL interface card.
see http://www.hp-collection.org/hpil.html
Posts: 1,193
Threads: 43
Joined: Jul 2005
Hi Luiz,
I hope you are doing well. There is a slight chance that a can find a copy of that advertisement, but it may take a long time, because (in case it's still there) the magazine with the ad is stored in a rather inaccesible documentation deposit and I'm currently very busy. If I find a time slot to go there, I'll try to find it for you... please be patient.
Just from my memory (but rather convinced): I think the ad, or a very similar one, appeared in the September 1979 issue of Scientific American magazine (USA edition). It was the special annual issue, with many articles about a main topic; in this occasion the main subject was "The Brain". It was the first official reference about the HP-41C, at least for me.