.HouseIn. Then, the 4 jacks of the cord are fed by 4 different signals such as digital PBx extension circuits that use Pins 3 & 6 like Panasonic PBx systems.- Jack #1: Pins 3 & 6 = DIGITAL Panasonic Compatible Digital Telephones- Jack #2: Pins 3 & 6 = DIGITAL Panasonic Compatible Digital Telephones- Jack #3: Pins 3 & 6 = DIGITAL Panasonic Compatible Digital Telephones- Jack #4: Pins 3 & 6 = DIGITAL Panasonic Compatible Digital Telephones Typically, the male plug of one EZ80002222 Cheater Cord is inserted into an outlet on the In.