IPhone Outgoing Voice Garbled on 3G and EDGE

Question

About 3 days ago, I started to experience an issue with my 3G iPhone running 2.2 software. On incoming and outgoing calls I can hear the person on the other end but my voice is garbled and/or filled with a lot of static. This occurs on both the AT&T EDGE and 3G networks with and without the factory-provided headset. However, if I switch the speakerphone function on, both parties can hear each other normally. What I thought was particularly interesting is that when I use Truphone to make a VoIP call, everything functions normally as well. While I first thought that this could be some sort of hardware issue, the last test made it seem more along the lines of a software problem. I have powered on/off the phone, rebooted the phone, restored it to backup and restored to a new phone all with the same result. Has anyone else experienced this issue and been able to resolve it? I have an appointment at the Genius Bar on Friday but am hoping to be able to resolve this on my own.
Thanks.

Answer 1

I was just posting this same problem on Mac Rumors. I'll paste the text here:
+Yesterday morning, I receive a call on my iPhone. I answer and they can't hear me. I hang up thinking it's a bad connection and dial them back. Same thing happens. I can hear them just fine, but they can't hear me.+
+1. I do the hard reset.+
+2. I do a full restore. Same problem. The only thing the other person can hear is a little bit of digital noise, like a swirly sound.+
+3. I call AppleCare and we go through the list of potential fixes. Nothing works. They send me to the Apple Store.+
+At the Apple Store, the Genius Bar guy knows the problem before I even finish describing it. He says, "I've seen this problem nine times today, so I am thinking it's an AT&T issue. But just to narrow down the problem, let's replace your hardware."+
+He replaces the phone with a new one and it works fine. So I go home and it works the rest of the day.+
+This morning, I get to the office and the same problem is happening again.+
+I know there are others on this forum who have experienced the same problem. But if it is happening to everyone at the same time, would it be an AT&T problem or an Apple problem?+
+If it's an Apple problem, replacing the phone should have worked. But if it's an AT&T problem, it should happen across the board, and not to just nine people that day. That Genius Bar guy would have been bombarded with angry iPhone owners.+
+Does anyone have any helpful insight on this problem (saying "AT&T *****" isn't helpful insight)+
+UPDATE: (January 7, 2009, 9:30am) I am on hold with Apple Tech support and they are trying to find a solution. As an experiment, we tried turning 3G off and it worked. Obviously, not a long-term solution, but effective for getting a call to go through.+
+Any other input? I will update this thread if I receive a helpful fix from Apple or AT&T. These threads aren't any help unless there is a solution posted.+