I ordered a ThinkGeek Bluetooth Retro Handset to use at home. When I come home I plug my phone in to charge in my room, but then I can't hear it ring elsewhere in the hosue. The idea was to take this handset which wirelessly connects to cellphones via bluetooth and place it in another part of the house so that I can tell I'm getting an incoming call. The only issue I have with that setup is that it ringing isn't any louder than conversations held over the phone, that is, the ringing is a little quiet.
The handset pairs with cellphones in the same manner as any other handset over bluetooth. It has an internal rechargeable battery which is charged via a standard USB port built into the base of the handset and it comes with a USB cable. Next to the USB port is the only button on the phone which is pressed to answer a call, hang up a call, or begin voice dial, held down to turn the handset on and off, and held down longer to begin pairing with a cellphone. There's a blue LED in one of the holes in the microphone portion of the phone which blinks to indicate if its on or trying to pair. Transitioning between on, off, and pairing produces a cute sound and a change to the LED.
Overal I'm pleased with its simplicity and use of common parts although I wish there was a way to adjust the volume of the ring.