So glad you asked!
This big boy is DISCONTINUED but sure does have some nifty instructions. Here we go!
To a Bluetooth Device
1) To put your headset in pair mode, press and hold the power button towards the Bluetooth icon until you hear "pairing" and the headset LEDs flash red and blue.
2) Activate Bluetooth on your phone and set it to search for new devices.
3) Select “PLT_Focus” from the Bluetooth list of on your device. If necessary, enter four zeros (0000) for the passcode or accept the connection.
4) Once successfully paired, you hear “pairing successful” and the headset LEDs stop flashing.
To a Computer Via Bluetooth Dongle
1) Insert the Bluetooth USB dongle into a USB Port of your computer. It should automatically go into pairing mode. If it does not, use a pen or a paperclip to press and hold the tiny dimple button on the right side if your USB dongle until the light on the dongle flashes red and blue.
2) Pairing is usually automatic. If not, put the headset in pairing mode by pressing and holing d the power button towards the Bluetooth icon until you hear "pairing" and the headset LEDs flash red and blue.
3) When paired you will hear “Pairing Successful” in the headset.
4) You will need to go in the computer settings and set Plantronics BT600 as the default device. This is the Bluetooth dongle.
NOTE: Your headset can pair with up to 8 devices but only maintain 2 connections simultaneously; this includes the Bluetooth USB adapter.
USAGE (See Photo 1):
Volume up and down is on the side opposite of the microphone at the top.
Play, pause and skip are on the same side in the center of the ear pad.
The power button is in the venter of the side with the microphone. This is also the button you use to answer calls.
The pairing button is above the side with the microphone.
Your mute button is just above the microphone.
Your battery and headset usage indicator light is just below the power/call answer button.
Your best bet for issues with this headset is to have your device forget the Focus headset (or in the case of a Bluetooth dongle, unplug the dongle) then follow the instructions above to pair it again.
If this doesn’t resolve the Customer’s issue (it usually does) get them over to Product Support!