On Wed, 11 Apr 2007, siddhant tewari wrote:
>                  Really great to get a answer ... i think my mobile phone
> has class 2 bt adapter ... but this issue is a real shock for me ... i
> thought if any of the devices has a good range , communication channel will
> be established and data transfer will take place , but all this theory goes
> in vain .
The problem is as simple as transmit power.  As wikipedia helpfully shows 
(http://en.wikipedia.org/wiki/Bluetooth#Uses), class 1 devices can have 40 
times the transmit power of class 2 devices, the class 1 connecting to class 
2 problem comes down to that past a certain range, the class 2 device does 
not have a high enough transmit power for its signal to reach the reciever 
(2.4GHz signals are eaten particularly fast by everything in their path, 
including air).

As i outlined before, the higher transmit power in a class 1 device will come 
coupled to a higher sensitivity reciever, but that's not going to get you 
100m.  If you had got the 30-40 metres you were attempting in your original 
email you would have been extremely lucky.

The problem is there are very few phones that come with class 1 bluetooth, 
100mW transmit power is a little hard on battery life.  If you want a 
challenge though, find a class1 bluetooth adapter that has a dipole aerial 
rather than the usual circuit board trace and attach a bigger one.