first i thought my iPhone has a hardware defect after all your answers didn't help (see http://www.modmyi.com/forums/showthr...9709#post79709) but after buying the apple bluetooth headset i think its maybe something else...
thats the symptoms: the headset is recognized and paired with the iphone. if a call comes in the headset makes a beeping sound, but if i click the button to answer: no sound coming from the headset (mic and earspeaker). if i switch the source to iphone i can hear and speak to the caller. switching back to the bluetooth headset (or the speaker phone): no sound. how could it be? the bluetooth headset makes a sound if i change the volume with the iphones buttons while reaching min and max values but sound isn't transmitted from and to the headset (and the iphone speaker).
i dont know if there is hope for me after doing some restores because i already did some without any change.