If the speakerphone is on, while in a call, the default sleep screen blanking time is active.
After the sleep time elapses, there can be _no_ way to activate the screen again without
hanging up the call.
The proximity sensor is disabled while the speakerphone is active.
The volume up/down buttons to not active the screen.
Camera activation by twisting is disabled
Accessibility/Power button ends call
The call must be hung up before any action can be done with the phone.
Suggestions for fixing:
When a phone call is set to speakerphone:
1. Have a call settings setup/selection mechanism to always enable the screen
2. Make the proximity sensor active and reactivate the screen when set/unset
3. Make the volume up/down buttons reactivate the screen
4. Make the accelerometer "force" sensor reactivate the screen similar to the active notifications alert mechanism