My
t-Mobile 7100T acts like the mic is dead and the ear piece is too. It will make and receive calls, e-mails, etc. but can't communicate sound wise?

Have you popped the battery out and back in?

yes, have wiped memory, battery in and out, etc. A former 7100 I had hap problems with mic intermittently

I just ordered one, and received it and it is doing the same exact thing...I sent it back for a new one!!

my 7100t was having problems with the mic going out and the people on the other end not being able to hear the words that were coming out of my mouth...all I did was smack the keypad against the palm of my hand a couple times and the mic kicks back in.

I have the same problem with mine, my mic is barely working the speaker is OK. I have resorted to using my bluetoothe headset constantly now. I have opened up the phone to fix the mic but i can't find it.