The Museum of HP Calculators

HP Forum Archive 13

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Infrared interface for 42s
Message #1 Posted by andrew on 21 Sept 2003, 1:48 a.m.

Does anyone know if the infrared output from the HP42s has been cracked and some method devised for capturing the print flow to a computer.

      
Re: Infrared interface for 42s
Message #2 Posted by Juergen (CH) on 21 Sept 2003, 6:36 a.m.,
in response to message #1 by andrew

I'm also highly interested in this matter. Somewhere I've read that the IrDA port available on many laptops is not suitable to receive 42S infrared signals.

            
Infrared interface for 42s - Info on MoHPC Forum Archives
Message #3 Posted by Andrés C. Rodríguez (Argentina) on 21 Sept 2003, 8:34 p.m.,
in response to message #2 by Juergen (CH)

Look in the MoHPC Archives around 2000 or 2001, there were many discussions about this, including a very detailed article from Steve (Australia) about connecting a phototransistor to the Audio In connector on a PC Sound board to successfully decode the HP42 IR stream.

      
Re: Infrared interface for 42s
Message #4 Posted by Nelson M. Sicuro on 21 Sept 2003, 7:26 a.m.,
in response to message #1 by andrew

I think that such device exists, please take a look at

http://pub21.bravenet.com/classified/show.php?usernum=1803468352

Regards,

Nelson

      
PDF docs for 82240
Message #5 Posted by Randy Sloyer on 21 Sept 2003, 8:57 a.m.,
in response to message #1 by andrew

No cracking necessary.

HP placed this information in the public domain so that other OEMs could use the 82240. The technical specs exist as a PDF document:

http://www.hpcalc.org/details.php?id=4742

IIRC, the 42S does an initial preamble that is not documented in the spec. It seems to be 3/4 of a word, ~90us on/~550us off, 16 reps. I think it must be used to clear the input buffer of the 82240.

Edited: 21 Sept 2003, 9:06 a.m.

      
Re: Infrared interface for 42s
Message #6 Posted by Emmanuel, France on 21 Sept 2003, 2:47 p.m.,
in response to message #1 by andrew

You could use the following interface:
Hook-µP by Rush Systems
It works with HP-28, HP-41 and HP-42
Good luck!
            
Re: Infrared interface for 42s
Message #7 Posted by Tom Cox on 21 Sept 2003, 4:12 p.m.,
in response to message #6 by Emmanuel, France

I have an HP-42S and the Hook-up device from Rush Systems, but long ago lost the software for it. Does anyone know where I might get a copy of software? Thanks.

                  
Re: Infrared interface for 42s
Message #8 Posted by Emmanuel, France on 23 Sept 2003, 12:55 p.m.,
in response to message #7 by Tom Cox

Done... ;o)

            
Re: Infrared interface for 42s
Message #9 Posted by Juergen (CH) on 21 Sept 2003, 4:32 p.m.,
in response to message #6 by Emmanuel, France

Anybody out there who has a Hook-µP interface for sale?

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