If you wish to read or write floppies between your Apple IIc and your PC, you will need a Din5 to USB/DE-9 adapter. The proper instructions for this are located here, along with purchase links:
IIc, Laser 128, and Franklin Ace 500 modem port (DIN5) cabling
But if you’re like me and don’t wish to spend 30+ dollars on a cable and USB adapter, then you can make your own! (But you’ll still need an USB adapter, maybe!)
Showing two cable ends coming out of a Tupperware container.
The process is fairly simple as long as you follow the instructions provided by ADTPro. One road block I came across was the proper order of the pins on the cabling. ADTPro shows the pin numbering for the DIN5 but not the DE-9. I used a female DE-9 but while wiring it I plugged the female side to a male to male cable to make sure I didn’t screw up the ordering. I used a multimeter set to check continuity throughout to check pins and wiring. I recommend using a female adapter as most normal de-9 cables and the port on the back of your PC would be male. (Warning, I nearly cut up a NeXT cable until I noticed what it was. I don’t know how I acquired it, but don’t cut up museum pieces!) The proper ordering for the DE-9 port is shown in the following graphic:
To protect the wire splicing, I used a Tupperware container with a hole built into one side to let the cable through. I used zip ties to hold the cable from moving. I used wire splice connectors to physically connect the two cables. I find these connectors are much simpler to work with and very strong. I used two different types in the image because I thought I may have had an interference issue, but it turns out it was the speed of the USB adapter I used.
Showing connector splices inside of a Tupperware container.
The adapter I purchased that seems of fairly decent quality was this one:
USB TO RS232 SERIAL DB 9 PIN COM Port Converter cable from besteworld
This adapter requires that you use a female DE-9 port. You should not need the driver CD. You will need to adjust the driver properties on Windows under “Device Manager” > “Ports” > “USB-Serial CH340”
Device Settings for USB Adapter
I set mine to use the maximum speed shown and then I no longer received any errors during transfers.
Shoot me an email if you have any trouble!