The Internal IR Connection cable is an internal cable, connecting between the IR circuitand an external IR receiver. On one side it has a 3.5mm jack which fits through a 6.4mmhole on the rear panel that lets you connect the External Remote IR Receiver cable. Theother side of the cable has a 4-pin connector that fits on a 4-pin header on the IR circuit.Once connected, the Kramer machine can be controlled from a distance using the includedIR Receiver cable (15 meters long). This distance can be further extended (up to 60meters) by using Kramer Stereo cables, 15 meter each (C-AS35M/AS35F-50).