This has happened to my phone once before, but it was corrected after I restarted the device. I had been using my iPhone (1st gen) quite a bit with the earbuds/microphone. But when I wanted to use it just as a handset the other day I got no volume from the speaker and none into the handset microphone. Increasing the volume from the external rocker switch did nothing, except indicating that it was increasing the volume through headphones - that were not attached! I've tried resetting the iPhone, restarting it several times, all to no avail. The phone works great through the earbuds and Bluetooth, just not as a regular handset. Any ideas ?