How to convert a serial port keyboard or mouse to a USB port

Updated February 21, 2017

A serial port on a computer peripheral, such as a mouse or keyboard, is equipped with a multi-pin plug for connecting to the serial port on the back of the computer's central processing unit. Converting this serial port device to a USB port may be desirable when the user upgrades to a newer, faster computer yet wants to continue using an older keyboard or mouse.

Insert the software CD-ROM in the computer's media tray and close the tray. The software disc should begin playing automatically. If not, go to the Start Menu, select "My Computer," then choose the drive (usually drive D:) for the media player and select "Run."

Install the software on the computer by following the on-screen prompts. The software contains the drivers that allow the computer to understand the serial connection signal even though it is attached via a USB plug.

Insert the serial plug on the end of the keyboard or mouse into the serial port on the adaptor cable. Be sure to align the pins inside the plug with the holes on the serial port on the end of the adaptor. Tighten the connection by turning the locking bolts clockwise on each side of the plug.

Insert the USB plug on the other end of the adaptor into a free USB jack on the computer. The flat, rectangular plug inserts in one direction only.


Converting to USB is more convenient since the cable simply plugs in and out of the USB socket in seconds, unlike a serial plug that must be aligned with the port and secured with a locking bolt on each side of the plug.


Turn off the computer while making the serial to USB connections.

Things You'll Need

  • Serial to USB adaptor cable
  • Accompanying software
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About the Author

James Clark began his career in 1985. He has written about electronics, appliance repair and outdoor topics for a variety of publications and websites. He has more than four years of experience in appliance and electrical repairs. Clark holds a bachelor's degree in political science.