Buzzing sound from my nokia 6510???

[ntung]

I can hear a very soft buzzing sound from my nokia 6510 when making/receiving calls and when using GPRS.
(the sound is like when putting your mobile phone near a speaker nut just very soft)


The sound i beleive is comming out from the phone not the speaker because when i use the hands free i hear no buzzing sound from hands free but still hear buzzing sound from the phone.


My friends nokia 6510 does not behave like that.
Is it normal???