UPDATE: An original DS-2 11.6 disk has been confirmed to boot with this dongle. Thanks for sending that info in.
Thanks to Hoy Brothers from 13th Floor BBS for sending me the results of tests on an original C-Net dongle. Between that, some cryptic info I found on old comp.sys.cbm posts, and lots and lots of testing, I figured it out.
This should allow all those oldschool sysops who lost their original dongles (like me) to load their original C-Net disks again. Should work with various versions. Not sure about C-Net 128, but I’d love feedback from anyone who tries this to confirm different versions it runs on. My original C-Net 12.0 runs fantastic now.
Parts needed: 4.7k ohm resistor (1/4 watt should be fine), 10uf non-polarized capacitor (5v minimum rating i assume), 1n4148 diode (the cheap ones you used to get in batches from radio shack), and a female 9-pin serial connector (for the joystick port).
Using the diagram on https://www.c64-wiki.com/wiki/Control_Port
Connect pin 7 to pin 9
Pin 5 -> 4.7k ohm resistor -> Pin 9
Pin 5 -> 10uf Non-polarized Capacitor -> Pin 9 (the resistor and capacitor run in parallel)
Pin 1 -> Anode of Diode – Cathode of diode -> Pin 5
That’s it. Let me know how this works out for you. Remember it plugs into port 2.
Versions confirmed so far: