So I have a Royal DS 2260. It's an ancient "digital organizer" from the late 90s.
It has a 2.5mm headphone jack that can be used to either send/receive data to and from other digital organizers and (using a special serial cable) connect to a "wintel" pc where it's contents can be synced to/from the device.
Well, I'm not paying some scalper on ebay way to much for that serial cable, so I tried to make my own.
But, it didn't work! But then, I got smart.
I know, after reading some pages on the ticalc website about DIY link cables, that the 9 pin serial port can be used (much like the parallel port) as GPIO.
So I realized that it's incredibly likely that this thing doesn't use the RX and TX pins, but instead the other pins on the DSUB connector that can be controlled by software.
Does anyone have any information about using the 9 pin serial port on "wintel" computers as GPIO? Because I didn't find much of anything on google.
Update: Yep, when the software enters sync mode, RTS changes from high to low.
