PerfectCue is a light and sound signaling system. It enables a presenter to send audio and visual cues to a projectionist using a wireless hand-held transmitter. It can also remotely control presentation apps such as PowerPoint on two computers simultaneously when they are connected to the USB ports. The computers "see" PerfectCue as a standard USB keyboard and require no special drivers. The actual keystrokes can be customized with a free app. By default, the keystrokes are "right arrow", "left arrow" and "b". These correspond to the green, red and yellow cue lights or the "Forward", "Back" and "Screen Blank" buttons on the transmitter PerfectCue responds quickly and reliably to commands from the transmitter. Additional cue lights can be interconnected with with Cat 5 or XLR cable and can trigger each other. Multiple cue light - transmitter pairs can operate independently on separate communication channels. In-Out 4-pin XLR jacks enable cue light sounds to be overlayed onto beltpack intercomm communications.