The TVGuardian LT acts as a smart remote control. The TVGuardian LT needs to learn your TV remote’s mute code. In order for the TVGuardian LT to learn the TV remote’s mute code, you need to hold the LRN/TST button on the TVGuardian LT until the input light starts flashing. Once its flashing, hold the TVs remote 6-8 inches from the front of the TVG LT and press the Mute button once. The input light should stop flashing. If it doesn't, try it again and making sure the remote is pointed at the front of the TVGuardian LT.
Once the TVGuardian LT has learned the TV remote’s mute, you need to find the IR sensor on the TV. This is usually located in the lower right hand side of the TV and is often visible. It also helps to move the IR cable eyes around the general area you believe the sensor to be while continuously pressing the LRN/TST button on the TVGuardian LT until the TV mutes. Once the TV mutes, you've found the IR sensor.
Once you've successfully gotten the TV to mute when pressing the LRN/TST button, you need to connect the yellow composite cable from the DVD player or cable/satellite box's video output port to the TVGuardian LT composite yellow CC input.
The TVGuardian LT is capable of muting two devices. If your sound comes from your TV speakers and a sound bar or surround sound speakers then you would put one “IR eye” on each devices remote control sensor. If your sound only comes from your TVs speakers then you will only need ONE of the “IR eyes”. You can separate them and wrap the unused one, out of site, behind your equipment.
Instructions for TVGuardian LT and How-To-Video showing connections:
http://tvguardian.com/TVGuardian_Support/tvguardian_support.html#.VNVCaPnF-ap