palmOne TREOTM TreoTM 650 Using Manual page 177

I can't make or receive calls using a hands-free device
with Bluetooth technology
Check all of the following:
• The Bluetooth setting is turned on in the Bluetooth application.
• Your device with Bluetooth wireless technology is charged and turned on.
• Your Treo is within range (30 feet) of the hands-free device.
• The Dialup Networking setting is turned off in the Bluetooth application.
• The Bluetooth application screen is closed.
Network connection :: 175