| Telephone: The telephone has twelve buttons, each of which beeps when struck by the hammer tool. Phone buttons can produce either a single beep or a continuous beep. You can place between one and three telephones and move them freely around the simulation window. In the telephone's Properties Box, you can choose to sustain the phone button. A sustained button sends out a continuous signal (the button's beep), just as the signal generator does. You must use the hammer tool to select the sustained button. You deselect the button either by selecting another button to sustain or by "hammering" the non-button part of the phone. The prehearing option allows you to hear the phone button beeps in Stop mode. Prehearing is on by default. The telephone is one of nine sound sources in Sound Lab.