I think there are similar questions around, but not exactly the same problem:
I just bought a Plantronics Voyager Legend UC. Like all "UC" models, the headset comes with a small bluetooth dongle. When plugging the dongle, it immediately pairs with the headset, all fine.
When turning to the "audio devices" a new device shows up: Plantronics BT 300. Using the PulseAudio volume control I can setup different profiles, like "analog mono output", or "analog mono duplex".
But unfortunately NO sound is reaching the headset.
Running Ubuntu 12.10 64 bit. Any idea anybody?
Actually the answer goes more like: "user error; read the manual more carefully".
This Plantronics has a little button called "play" (directly at the beginning of the micro boom). This button is used to enable/disable transfer of audio input/output between headset and dongle.
After I figured that ... no more problems.
EDIT: checking the manual again I found that it is somehow misleading:
a) the button you have to press is the "call" button (the one with the phone icon next to it in the manual drawings)
b) the "play" button ... is actually the mute button on the boom
(I assume that "call" enables/disables the audio stream from your computer; whereas "play" might really "pause"/"play" when you are using Windows and media player ...)
Make sure the blue light on the USB dongle is lit, and make sure you heard the "PC Connected" message in the headset. If not, with your head set on, pull out the USB dongle, and reinsert it; wait until you hear, "PC Connected."
Repeatedly press the increase volume (+) button on your headset until the device says, "Volume Maximum."
Launch Pule Audio "Volume Control." On the Configuration tab, select Analog Mono Duplex for your Plantronix device.
On the Output Devices tab, make sure you've selected "All Output Devices" from the "Show" drop down.
Then, select the check mark next to your Plantronix device.
The port should be (default) Analog Output.
Now, right click on the Speaker icon in the Unity Indicator bar (Task Bar). Select "Sound Settings..." to open the Sound dialog window.
On the Output tab of the Sound dialog, select your Plantronix device.
Make sure the Output Volume slider is not muted.
You can then click the Test Sound button, and you should hear some test "staic" in your headset.
I had a similar issue, but non of the above answers worked for me. My solution was to physically take out and reinsert the BT600 usb device.