Bluetooth

So as you can tell I like bluetooth a lot. Here's a question though.
I have a logitech bluetooth keyboard and mouse. I also have a
bluetooth motorola stereo headphones (i believe they are the HS820).
They pair and work out fine, but when I go to play a song, they are
incredibly staticky and my mouse and keyboard go nuts. Typing is
very erratic as well as the mouse movements. From my knowledge of
bluetooth technology, this isn't suppose to happen. So why is it?
And what can I do to eliminate this interference?

Bluetoothguy wrote:

So as you can tell I like bluetooth a lot. Here's a question though.
I have a logitech bluetooth keyboard and mouse. I also have a
bluetooth motorola stereo headphones (i believe they are the HS820).
They pair and work out fine, but when I go to play a song, they are
incredibly staticky and my mouse and keyboard go nuts. Typing is
very erratic as well as the mouse movements. From my knowledge of
bluetooth technology, this isn't suppose to happen. So why is it?
And what can I do to eliminate this interference?

A quick glance at this page, suggests Bluetooth is well armed for
dealing with RF problems.

http://www.mit.edu/~ddaly/projects/b...frequency.html

What it cannot protect you against, is things outside the Bluetooth
standard. Say your Bluetooth transmitter is fed by USB - will
the USB always be ready when needed ? According to this, audio
uses Synchronous Connection Oriented channels (which in other
places would be called CBR or constant bit rate).

http://pegasus.cc.ucf.edu/~rmccrave/...gnsolution.htm

http://en.wikipedia.org/wiki/Bluetooth

On the face of it, it looks like it should all work. A piconet can
supply
more nodes than you are using, so that is not the problem. Bluetooth
supports SCO and ACL channels - the audio would be SCO, and the ACL
would
have to steal whatever time slots or holes that are left. It means
the Bluetooth keyboard and mouse, have to honour the higher priority SCO
requirements of the audio node.

The scariest part of Bluetooth, is trying to figure out what version
of standard every component you own, has been designed to. Many times
I read a description of the way something works, and then I see mention
of yet another "profile", and it leaves me wondering if the description
I just read, is the way it works or not.

If your Bluetooth dongle is plugged into a USB port, look at the port
for a moment. USB ports are in stacks of two. If you plug the Bluetooth
dongle into one port of a stack, try leaving the other USB hole blank.
Just on the off chance, that other async activity on the USB port, may
be interfering with timely delivery of data to Bluetooth.

The Wikipedia article mentions this:

"Most bluetooth stacks implement the SCMS-T copyright protection"

and that makes me wonder whether a very low quality standard is being
used to send audio to the headphones. Does the audio sound better if
it is sourced by a cellphone ?

This stuff isn't complicated enough...

Yeah, I know, users aren't supposed to need to debug this stuff.

The data rates involved are low enough, that there really shouldn't be
a problem. The erratic behavior almost suggests the devices aren't
all working to the same standard.

Phone up Motorola tech support and ask them what's up ?

And if you like to research these things for yourself, try recording
the audio coming from the headset. Use a program like Audacity, to
send a sine wave (tone) over Bluetooth. Use another program or a
separate
computer, to record the audio. Compare the sent and received waveforms,
and
inspect them for phase shifts, time shifts, waveform "flat spots" caused
by data underrun, and so on. Ideally, you would want to open up the
headphones and pick up the analog signal feeding the earpiece, to get a
more accurate picture of the signal coming from the output of the
Bluetooth receiver chain.

Now, wouldn't an Ipod make this easier ?

Paul