A really handy feature I discovered today that works on my iPhone4 on O2 is a way to divert all my incoming calls to my voicemail. This is handy for many reasons. As I frequently use my iPhone during social media coaching sessions and seminars with my clients, there is nothing more annoying than having someone call me mid flow or whilst I am showing someone how to use Apps like Hootsuite on the phone; Or when I am using the phone to record a video. I know the iPhone comes with Airplane Mode but it then affects my 3G access to the internet.
The solution is to divert all calls to Voicemail.
To activate the divert :
**21*901# Then hit the Call button
To deactivate the divert:
##21# Then hit the Call button