Beehive B100

MMcM

11 Jul 2020, 23:29

This is the keyboard from inside a Beehive B100 terminal.
Beehive-top.jpg
Beehive-top.jpg (448.4 KiB) Viewed 1304 times
The wiki has photos by snuci, who has a complete terminal. The chips in this one all have 76 date codes and that has a couple 77 and so is perhaps a little younger. The custom controller IC and socketed ROM aren't quite the same, but everything else pretty much is. So I won't bother with more photos of the one here.

I couldn't resist the atomic beehive logo on the PCB. Of course, those might conceivably be stylized bees and not electrons. And likewise the company name might not indicate any deeper LDS connection than just made in Utah.

Below that logo is the Key Tronic logo. So the first step in getting this board working again was replacing all the decomposed foam. The result isn't great to type on: maybe I wasn't choosy enough with the replacement foam.

But these early Key Tronic boards with tall switches and spherical double shot ABS key caps with extra-rounded corners are quite nice to look at. The beige-with-black and brown-with-white, see original photo from manual, isn't as striking as some with colored keys. But it has yellowed to cafe-au-lait and mocha a bit more gracefully than some of the reds and blues have.

The ribbon cable to the terminal had 18 conductors. That would probably be a too many if it were detachable, in which case some signals would have to be encoded. The basic communications protocol is parallel ASCII: seven bits of data and a strobe bit. I generally just have keyboards like that emulate a serial port, so one can type but not fully control the operating system. Consequently, there is no software work for this one, just updating the README on the program I already have.

And the converter is just an 18-pin DIP to fit into the connector and wires to a Teensy.
Beehive-converter.jpg
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This keyboard does not have the optional functional keys. The switches in the rightmost section of the keypad are all there, but the leftmost column with special action keys lacks those caps. And the rightmost column of modes only has ALPHA LOCK. The rest of the switches in that row still have the LEDs and they still toggle when pressed and affect the corresponing output signals. It might have been harder to see this when mounted inside the terminal without the key caps with a window.

The navigation keys were apparently internal to the keyboard, moving the cursor without sending anything to the host. Interestingly, they send the same letter as the corresponding VT52 escape codes. But instead of being prefixed by ESC, another signal on the connector, INTERNAL OPN is toggled. EOS J, EOL K, UP A, DOWN B, RIGHT C, LEFT D, HOME H, CLEAR E.

Pressing BREAK toggles the BREAK EN signal for a few hundred milliseconds. I could make this control the break bit in the device control line state of the CDC ACM driver. But I don't have anything on the PC that cares.

Occasionally the @ ` key sends the normal ASCII character followed by a 30 character mix of internal and not internal and of fixed and variable. I presume this is some defect of the board, but I do not yet have a hypothesis what that could be.

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