Your Unifying USB receiver can be paired with up to six Unifying devices at a time. You can determine if your Logitech devices are Unifying by this logo: 

You can connect devices to your Unifying receiver using Logitech Options software. If you don't already have Logitech Options installed, you can download it from www.logitech.com/options.

To connect your device:

1. Launch the Logitech Options software:
   Start > Programs > Logitech > Logitech Options
2. At the bottom right corner of the Welcome window, click ADD DEVICES.
3. In the "Add a device" window, click ADD UNIFYING DEVICE.
4. Follow the on-screen instructions to turn your device off and then back on.