Jason Lindquist (jlindquist) wrote,
Jason Lindquist
jlindquist

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It's been a fairly productive couple of weeks. I was going to eBay off my old Personal LaserWriter NT (I replaced it last year with an HP LaserJet 1200,) but Karen mentioned it might be useful in her Spanish classroom. PHS is mostly a Windows shop, but MS has always included LaserWriter drivers--back in the day, Apple made the only remotely affordable laser printers (four digit prices, not five.) Lots of purely DOS and Windows shops had an Apple LaserWriter. I just needed to get the PLW's speaking RS-232 serial, and at a decent speed. Pushwheel setting 0 is standard PostScript 1 batch mode over LocalTalk. Setting 5 is PostScript 1 batch over serial on either the Mini-DIN 8 port or the 25-pin D-Sub port at 9600 baud. Someone in England had a nice guide for connecting a LaserWriter IINT this way, complete with a shell script for tweaking settings. The script let me bump the port speed up to 57,600 bps. It's much slower than 230.6 kbps LocalTalk, but it's functional. (Never mind the Canon LX engine inside only does four pages per minute at 300dpi.) It's not the prettiest thing out there, but it's free. I modified a 9-25 pin serial cable to the null-modem configuration neccessary for this, and it works like a charm.

I borrowed one of the Daktronics scoreboard controllers from the gym to figure out its workings. Disassembling its program EPROM will be a pain in the ass. Texas Instruments doesn't provide online documentation for the TMS70C02 microcontroller inside it, it's a long-obsolete part. I previously hadn't had any luck analyzing its output. It ran much faster than my old oscilloscope could resolve. The Tektronics TDS 1012 digital storage scope I bought a couple years back has more than enough bandwidth to do the job. It looks like the output is actually RS-422 differential serial running at 12,800 bps. That doesn't look like something I can easily transmit or recieve with a standard PC serial port, but it shouldn't be too difficult to come up with a USB microcontroller dongle that will. Naturally, that device will also handle the Nevco and Fair-Tron/Fair-Play/Trans-Lux/Whatever they call themselves this week protocols I decoded previously.

(Edit: Fucking finally! Nevco added basketball double-bonus indicators to its boards. Daktronics did it last year, and Fair-Play the year before. All three of the majors have finally arrived at the party the National Federation and NCAA started fifteen years ago.)

While I had the controller at home, I figured I should finally print the keypad overlays I designed for wrestling and volleyball at the time I created the basketball overlay on the other controller. The factory overlays had all been lost or damaged, and the school had resorted to photocopied replacements out of the manual onto transparency stock. They were blurry and clumsily taped to the keypads. I originally designed them in SuperPaint on my old (System 9.2) G3 desktop. I took the opportunity to re-do the designs in AppleWorks 6 and make them public as PDF files. It's unlikely that anyone reading this regularly would find it useful -- how many people have a 1992-2003 vintage Daktronics scoreboard lying around? But it doesn't hurt to let the search engines find them.
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