Bluetooth™ Headset HBH-610a support with K510i

Accessory instructions: HBH-610a
Make sure the headset is fully charged, switched on and within 1 m (3 ft) of the phone.
The first time you turn your headset on, it immediately goes into pairing mode. The light flashes red and green. If so, proceed to the phone instructions below.
To manually prepare the headset, press the Volume buttons, (+) and (-), at the same time for approximately 5 seconds until you hear a long high-frequency beep and the light flashes red and green. The headset is now in "Pairing mode".
Phone instructions: K510i
Go to Menu > Settings > Connectivity.
Select Bluetooth > My devices.
Select New device, "Add".
The phone starts searching for devices. Make sure the Bluetooth accessory is in pairing mode.
When the accessory becomes visible in the Devices found menu, highlight it and press "Select".
Enter the Passcode (0000 by default) and press "OK".
The accessory is now added to the list of paired devices and is ready to use.