CallGuard is a free application that can help you to control outgoing calls on your Treo smartphone. What is CallGuard do? CallGuard can do only one thing. It make short Treo vibration then the subscriber which you calling answer to your call. Why need to vibrate Treo? Short vibration is need when your walking or driving without headset. Or in any other case when you cant keep Treo near the ear while calling. Which devices support CallGuard? CallGuard can run on any Palm OS based Treo device. How to install CallGuard? Install CallGuard just like any other Palm OS application. After installation process CallGuard will request for reset.