Assalam-o-alaikum

I Needed Some Information About Mobile Numbers Codes. I Have A Few Question . I Have To Give A Assiment On Mobile Numbers Codes. Kindly Anyone Who Know Do Reply.

1) Why Every Company Has It's Own Codes ? I Mean ( O333, 0300........)

2) Why A Company Changes Its Code ?( Like Ufone First Started With 0333 , Than 0334 And Now So On )

3) How Bluethooth Works In Mobile ?



These Are The Questions , Given To Me In An Assisement .
Kindly Reply