When engaged in a phone call there will be a small speaker icon in the bottom centre portion of the screen. That is for the speakerphone. To enable the speakerphone option press the centre button that has the letters "OK" on it. Once the speakerphone is enabled, the small speaker icon will now have a small red 'x' beside it. This indicates that you press the "OK" button again to disable the speakerphone.
