Somebody pointed me to this HP-41 with an unusual custom interface, see pictures. Has anybody seen such an interface before? Or does anybody even know what it is for? Any hints and suggestions welcome!
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HP-41 Unknown Interface
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Post: #3
08-27-2011, 12:58 PM
 I looks like a cereal port used to dispense the barley for your lager unit. <Ducks>
Post: #5
08-27-2011, 04:52 PM
Based upon the position of the wires that I can see connected, the interface is a simple extension of the keyboard row and column matrix, allowing external switches to input data into the 41.
Post: #6
08-27-2011, 04:57 PM
Just guessing, it may be a "paralell keyboard matrix" interface, in which external switches simulate keypresses. A 3x3 matrix, allowing (for instance) for digits 1 to 9 (but not 0) can be done with six wires, as shown. If someone wanted to export the HP41 bus signals (clocks 1 and 2, Flag Input, Data, ISA) it would had make sense to pick them at one of the backplane ports Again, this is just a quick guess. ▼
Post: #7
08-27-2011, 05:28 PM
There appear to be three more wires, terminating somewhere on the reverse side of the circuit board. It's nine pins, built inside what looks like an HP/IL female connector. ▼
Post: #8
08-27-2011, 06:58 PM
With three more wires a 5x4 matrix is possible, allowing for numeric data, decimal point, R/S and some more...
Post: #9
08-28-2011, 02:24 AM
Wow, that's elaborate hacking - wonder if it's part of a data input mechanism different from the original keyboard - maybe an industrial bar-code reader?. I have no recollection of such being published anywhere, but yet, the 41 series was such a versatile platform - and this proves it again. Edited: 28 Aug 2011, 2:59 a.m. |