Apple iPhone/iPhone 3G (User manual) - Manual (Page 45)

Chapter 3 Phone 45
Bluetooth Status
The Bluetooth icon appears in the iPhone status bar at the top of the screen:
 (blue) or (white): Bluetooth is on and a device is connected to iPhone. (The color
depends on the current color of the status bar.)
 (gray): Bluetooth is on but no device is connected. If you’ve paired a device with
iPhone, it may be out of range or turned off.
 No Bluetooth icon: Bluetooth is turned off.
An icon showing the headset battery status ( ) also appears in the status bar when
iPhone is connected to an iPhone Bluetooth Headset.
Routing Calls Back Through iPhone
When iPhone is connected to a Bluetooth device, you listen to calls through iPhone by
doing one of the following:
Answer a call by tapping the iPhone touchscreen. 
During a call, tap Audio on iPhone. Choose iPhone to hear calls through iPhone or 
Speaker Phone to use the speakerphone.
Turn off Bluetooth. In Settings, choose General > Bluetooth and drag the switch

to Off.
Turn off the device, or move out of range. You must be within about 30 feet of a

Bluetooth device for it to be connected to iPhone. To turn off the iPhone Bluetooth
Headset, press and hold the button until you hear the descending tones.
Unpairing a Device from iPhone
If you’ve paired iPhone with a device and want to use another device instead, you
must unpair the first device.
Unpair a device:
1 In Settings, choose General > Bluetooth and turn Bluetooth on.
2 Choose the device and tap Unpair.