source:
How to get better call quality on your droid - SmartPhoneADDICTED
THIS IS THE PHONE PROGRAMING MENU! DO NOT MESS WITH OTHER SETTINGS IN THIS MENU IF YOU DONT KNOW WHAT YOU ARE DOING! YOU CAN AND WILL FUBAR YOUR DEVICE!
How to get better call quality on your droid
There have been a few reports of users hearing a echo when making calls. Or the person on the other end of the call no being able to hear you very good. This is something that may help you if you find the Droid having poor call quaility.
On your dialpad dial*##PROGRAM
* then press* SEND
The SPC password is* 000000
Now you should be at the Programming Menu.*
From the list press*"04 Vocode"
Now you can select 13k, EVRC (default option), or EVRC-B. Select EVRC-B
After you select one, back out to your home screen and your phone will reset.
That's it Also here is a little information on what this does*exactly.
Wikipedia, the free encyclopedia Enhanced_Variable_Rate_Codec
Enhanced Variable Rate Codec B - Wikipedia, the free encyclopedia
Now before you dive into changing these settings... EVRC-B is not available in all parts of the country. So if you change these settings and cannot make calls, try changing it to the 13K setting.
ALSO THIS IS THE PHONE PROGRAMING MENU! DO NOT MESS WITH OTHER SETTINGS IN THIS MENU IF YOU DONT KNOW WHAT YOU ARE DOING! YOU CAN AND WILL FUBAR YOUR DEVICE!