If you have trouble pairing your Bluetooth phone with your Mac, or maintaining a reliable connection, these tips should help.

1. Some phones will generate the confirmation code automatically and prompt you to enter that code at your computer. Others expect you to enter a code of your choice at the phone, and then enter the same code at your computer.

2. For Mac Pro systems, make sure Bluetooth is available (on some models it was optional), make sure the external Bluetooth antenna is attached (if one was provided), and make sure that you have an unobstructed view to your phone.

3. In most cases pairing is not difficult, but it's not obvious how to do it. Remove any previous pairings you don't need (on either side) by forgetting or removing the corresponding devices. Make sure your phone is "discoverable". Then choose "Set Up Bluetooth Device..." from your Mac.

4. If your Mac does not show your phone after about a minute, double check to make sure that your phone is set it to be discoverable.

5. If you have a Bluetooth headset or other Hands-Free device, make sure it is turned off or out of range. The iPhone can only communicate reliably with one device at a time.

6. Remove any old pairings and turn off any Bluetooth services you don't need. Sometimes removing an old pairing and starting over can help. To remove a device pairing on iPhone, navigate to Settings -> General -> Bluetooth, tap on the ">" symbol in a blue circle next to the device name, then tap on "Forget this Device". To remove old pairings on the Mac, navigate to "System Preferences -> Bluetooth", select the device from the list on the left, and press the "-" button below the table.

7. Try again after a a little while.  Bluetooth uses the same unlicensed frequencies as 802.11b/g along with lots of other stuff. It's generally resilient, but can fail sometimes from heavy interference. If you have an AirPort Base Station or other transmitter in close proximity, this could be a source of interference. If you suspect interference or some other configuration problem, Option click on the Bluetooth Menu bar item to access Bluetooth Diagnostics. Select "Open Bluetooth Explorer", and then navigate to "Bluetooth Explorer -> Devices -> Connection Quality Monitor". This will show what devices are currently connected, and the quality of each connection.

8. Reinitialize the Bluetooth stack as follows:

- Quit Phone Amego (if it is running).
- Turn off Bluetooth
- Manually remove the preferences file located at: /Library/Preferences/com.apple.Bluetooth.plist
- Turn on Bluetooth
- If you are not able to turn Bluetooth off and back on, restart your system after removing the Bluetooth preferences file.
- Start again by pairing your phone with your computer.

In one particularly stubborn case, it was necessary to restart the iPhone before it would pair with a new iMac. To restart your iPhone: Press and hold the Sleep/Wake button until the red power off slider appears; Turn off your iPhone; Then press the Sleep/Wake button momentarily to restart your phone.

In my experience, Bluetooth can be a little fussy when you are initially establishing communication with a device, especially if you are upgrading from a previous Mac or iPhone. The reason is that there are so many potential devices and roles that things sometimes get confused or out of sync (you might still be paired with a previous iPhone or Mac that has the same name for example). If it doesn't work the first time, don't be discouraged. One or more of the steps above will usually help. Once you get it working, it's generally very reliable.

Notice that being "paired" means two devices are ready to communicate (no application data is being exchanged yet). Being "connected" means a client on one side of the Bluetooth radio link has established a connection with a compatible service on the other side. It is not necessary for your phone to show it is connected in the Bluetooth preferences panel to add your phone as a telephone device in Phone Amego. Once Phone Amego has connected, the Bluetooth preferences panel will reflect this. Phone Amego will not be able to exchange data with your phone until the Device Status is "Connected and Ready".

Mac OS X 10.7 may allow you to browse for a compatible Bluetooth service before your devices are paired and then ask if you would like to pair them. In my experience, this feature of Mac OS X does not work. Pair the devices first by setting up a Bluetooth device from your Mac. Then add the device in Phone Amego by selecting a compatible Bluetooth service.

In one extreme case, it was necessary to replace the built-in Bluetooth hardware with a 3rd party Bluetooth dongle to get Bluetooth audio to work on Mac OS X. Other sites have documented Bluetooth pairing issues as well.

For more information, please see:
Understanding the Relationship between Phone Amego and Bluetooth