I have two Telrad 816 analog systems that we would like to add music on hold to. I have a manual that shows a schematic of how to do this. Does anyone know where a pre made wiring system can be bought. The schematic shows a 50 position dual row ribbon cable, a 1 to 1 600 ohm Audio Isolation transformer, two 1800 ohm 1/4 watt 5% resistors. It also states that in order to eliminate the "Tone on Hold" pins 45 and 3 should be shorted. Any assistance with this would be grately appreceated.