 Each output of the array also had a P lead with two coils on each crosspoint of that output level.The two windings controlled by the same level were unequal, and were wound around opposite ends of the reed, in opposing polarity.When a pulse passed through the crosspoints of a level, the two ends of each reed were magnetized north to north or south to south, thus repelled each other and opened the crosspoint in all except the selected crosspoint.