Gregory's ServerThe short-lived optical parallel port brought numerous advantages to the interconnectivity table. Advantages included small size for the era, transfers free of electrical noise, the speed of parallel transfer, and the convenient ability to debug protocols just by having a look.
NanoRaptor
24 comments
Kroc Camen
@NanoRaptor The screws can be pushed in for single-stepping; the number of support calls I had to field where someone brushed the connector and paused all communication  
Skritch Monster Collie
@NanoRaptor a cable with a segmented LED (LCD? idk) display within the connector? I have questions, like why, how, and uh... idk just I'm a bit blown away  
Chris [list of emoji]
It had (and continues to have, to some small extent) success in industrial applications where it's necessary to connect an off-the-shelf computer to equipment with poor power conditioning.
rl_dane
@NanoRaptor Also, it used a DE-9 connector, but IIRC gender-reversed from the typical serial port DE-9. 
Andrew
@NanoRaptor so I know this is a joke but i’m aware of a domain specific interconnect that isn’t that far off
nonspecialist
@NanoRaptor there was a short lived 2-word (16 byte) Centronics shape version as well, but the LED segments were so small that they often got blocked by mites, and you needed a magnifying glass to debug the protocol 
rhempel
@futzle @NanoRaptor ... How do you have the time to write down the ASCII chars frame by frame? Thanks for saving me the time!
Deborah Pickett
@rhempel I … didn’t. Just noticed it started on 6e and ended on 70 and flashed 20 at about the right rate for a 5-5-4-3-2 word distribution and made an educated guess. @NanoRaptor 
Aethylred
@NanoRaptor yeah, but did you ever spend 3hrs trying to get them to work only to find one was green and the other was amber |
@NanoRaptor I can see someone in an office breathing on the end of the cable and wiping it on their shirt.
“That’s got it. Try printing again.”