The Kenwood TH-D74 radio uses a USB-A to Micro-B cable to connect between a USB port on your computer and the USB port on the side of the radio. Kenwood drivers that correspond to the USB electronics built into the radio are used by the device for the connection. They are installed with the KRS-D74 program setup. If you suspect problems with the drivers, see other Knowledge Base articles on this page (but be sure to give the device time to set itself up when you first connect it... this can take a minute or so). This radio does NOT use the more standard USB-K4Y cable into the mic jack of the radio.
The correct cable is an "Android" style connector on the cable. You may have one of these from another device in your collection (phone, camera, electronic reader, etc). However, these are not all created equally. Some are charging cables and not wired properly for data transfer.
If you have one of these cables, try it. If it works, great. If it does not, try another or get the RT Systems RT-49 cable. We guarantee the RT-49 to work with the radio and the KRS-D74 programmer: and you have our help to get things going.