Firstly, hold and press the red hangup/power button to turn the handset off. Then press it again to turn it on.
Then press and hold the WiFi button (labelled 1 in the picture below) on the base until the handset LED (labelled 2 in the picture below) starts to flash, this will activate the base discovery mode:
Then press the Reg softkey on the handset. Wait for the handset to detect the base. Once it has detected the base it will display a MAC address (e.g. 00-C0-33-E4-90-79), click OK on the softkey and then it will ask you for the passcode. Enter 0000.
The handset is now paired to the base.
