HI,
I've been working with the GMS shield for a couple weeks now, but i'm at the point in need to set up voice calling. I don't believe i have a software issue, but just a hardware issue. When i establish a call, my speaker is unclear and crackly. I'm just trying to use the speaker and mic setup from the GSM tutorial guide.
In the picture i attached there are two parts circled in red. I assumed they were some zener diode. Can any specify exactly what these are suppose to be? If they are some kind of diode, what rating should it be? also, do i need anything for the "differential layout"? I think these are my problems. Thanks.
