The Commodore serial cable
The Commodore serial cable connects Commodore drives to Commodore machines. It's compatible with all Commodore machines and with all Commodore drives and clones that have the usual serial bus port.
Hardware requirementsYou need the following hardware to make use of this cable:
All Commodore softwares support this cable.
You can find the details on how to build this cable at the construction page.
Connect the two serial plugs into the serial ports on your Commodore drive and your Commodore machine.
The Commodore serial cable is © Commodore Business Machines, 1979.
Source: The Joe Forster-STA homepage