To pair Logitech keyboard K400R with your computer, insert the included Unifying Receiver into a USB-A port and turn on the keyboard, the connection happens automatically. If your keyboard has lost its pairing or you need to connect it to a new receiver, use Logitech's free software to re-establish the link in under a minute, the same Unifying software also lets you pair Logitech k520 keyboard if you upgrade later.
Before you start: what you need to pair your Logitech keyboard K400R
Gather the keyboard, the Logitech Unifying Receiver (a small USB dongle), two AA batteries, and a computer with an available USB-A port. The receiver stores securely under the battery cover on the keyboard's underside, slide off the cover to access it. This receiver uses Logitech Unifying technology, which lets you connect up to six compatible mice and keyboards to a single dongle.
Step 1: Install the batteries and turn on the keyboard
- Open the battery compartment on the back of the keyboard by sliding the cover off.
- Insert two AA batteries, matching the positive (+) and negative (-) ends to the markings inside the compartment.
- Replace the battery cover securely.
- Locate the power switch on the top edge of the keyboard and slide it to the On position.
The keyboard features a power-saving sleep mode that activates after a period of inactivity, helping extend battery life. Press any key to wake it.
Step 2: Plug in the Unifying Receiver for automatic setup
This is the only step needed for most new K400R keyboards. Insert the Unifying Receiver into a USB-A port on your computer. With the keyboard turned on, the connection establishes automatically within seconds, no software or button pressing required. This plug-and-play process works out of the box for Windows 7 and later, Android 7 or later, and Chrome OS.
Step 3: How to re-pair your K400R using Logitech software
If plug-and-play fails or you're connecting to a different Unifying Receiver, use Logitech's pairing software to connect keyboard manually.
- Download and install Logi Options+ or the Logitech Unifying Software from Logitech's support site.
- Launch the software and ensure the Unifying Receiver is plugged into your computer.
- Select "Add Devices" (or the equivalent option in your chosen software).
- Turn on the keyboard if it isn't already, then follow the on-screen prompts to complete pairing.
For full customization, including mapping function keys and touchpad gestures, Logi Options+ or Logitech SetPoint (for Windows 8) is recommended.
Step 4: Test the keyboard and touchpad
Open a text document or any application that accepts keyboard input. Type to confirm all alphanumeric keys register correctly. Test the function keys, multimedia hotkeys (such as volume and playback controls), and the integrated touchpad, ensure scrolling, tapping, and gesture support work as expected. The K400R offers enhanced touchpad gesture support and programmable hotkeys compared to earlier models.
Troubleshooting common K400R pairing problems
If the keyboard does not connect, check the battery orientation and replace them if needed. Remove and re-seat the Unifying Receiver, or try a different USB-A port. Move the keyboard within 33 feet (10 meters) of the receiver and eliminate potential interference from metal surfaces or other wireless devices. If these steps fail, re-pair using Logi Options+ or the Unifying Software as described in Step 3. For a lost receiver, consult Logitech's guide on replacing or purchasing a new Unifying Receiver, or you can connect a Logitech wireless keyboard to a different receiver you already own.
For more general instructions, learn how to connect keyboard models from any brand.
