WMPoweruser.com

We have seen a little utility recently which selectively  routes sound to your speaker and earphone.  Teksoft has released a more polished version of the utility, ideal for use with VOIP applications.

The freeware is still based on their dynRil software and features the following fixes and features:
-microphone muting fixed
-cab with custom install location
-command line & smartphone support

The feature can be accessed from any screen by using the title-bar icon. 

The first icon routes the audio to the earpiece speaker.
The second blue icon, can be used to route the audio to the backspeaker.
The orange icon, routes the audio to the speakerphone, while in a phone call.
You can also use the bottom slider to move the taskbar icon, or the about button to show this page.
The top-right square hides the user interface.

Command line
This tool can be executed by command line with parameters.

You can execute /program files/teksoft/audioRoute/audioRoute.exe with the following:
-earpiece , routes the audio to the earpiece
-backspeaker , routes the audio to the backspeaker
-speakerphone , while in a phone call, activates the speakerphone
-switch , toggles between earpiece and backspeaker

Download the freeware from Teksoft here.