The stations use 2 pair and yes they connect up to the 25 pair amphenol on the upper left of the ksu circuit board.The CO lines connect to the jacks on the bottom of the ksu but there is also a jack there for ext. 32 which you program from.Stations punch down from the w/bl w/o pair which is ext. 31.All programming for this switch is done from a telephone connected to ext. 32.There is a slide switch on the bottom of the ksu to enable programming.