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Keyboard Builders' Digest / Keyboard Spotting

Intel MDS 225

An Intel MDS 225 with a divine key arrangement posted by absurd_logic589.

KBD.news
Published October 18, 2021
Creators! Feel free to tip me off about your keyboard related projects to bring them to 120K readers.

Part of the Intellec Series II Microcomputer Development System (->MDS), this vintage 60% keyboard design from around 1978-1980 features some interesting legends and functions.

From the back sticker:

CURRENT: 5.4AMPS

Seeing the photo with the TPWR key (in the cross shaped arrow cluster) I was hoping for a dreadful and imminent solenoid attack but no, according to the manual (thanks Se7eNBRC), it is the humble Caps Lock from a time keycap legends weren't standardized yet.

What do you think? Does the text really suggest this is an inverse Caps Lock?! What does "deselect" mean in this context:

[…]the TPWR (typewriter) key is used to partially override the SHIFT key in that when the TPWR key is deselected, alphabetic character keys always produce an upper-case code. The TPWR key, which is mechanically latched on or off, does not alter the codes of the numerical or any other non-alphabetic keys.

Btw, the manual is quite informative, describing the matrix, extended keycodes, N key rollover, etc.

To enable the detection of keystrokes, the keys are logically organized into a matrix of rows and columns. Since there are 62 individual keys, an 8-by-8 matrix is used. Strobes are sequentially applied to the individual rows, and all columns are continually monitored. When a key is depressed, the associated row strobe is applied to the corresponding column output to the 8041 [chip]. The known row strobe output combined with the active column input allows the 8041 to identify any depressed key.
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Published on Mon 18th Oct 2021. Featured in KBD #48 (source).


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