1. A VIDEO SWITCHING NETWORK COMPRISING CHASSIS MEANS; CIRCUIT MEANS ON SAID CHASSIS MEANS INCLUDING INPUT BUS MEANS, OUTPUT BUS MEANS AND CONTROL BUS MEANS; SWITCH MEANS PLUGGABLY DISPOSED IN SAID CHASSIS MEANS INCLUDING INPUT CIRCUIT MEANS CONNECTABLE TO SAID INPUT BUS MEANS, OUTPUT CIRCUIT MEANS CONNECTABLE TO SAID OUTPUT BUS MEANS AND CONTROL CIRCUIT MEANS CONNECTABLE TO SAID CONTROL BUS MEANS; MEANS FOR CONNECTING SAID INPUT, OUTPUT AND CONTROL CIRCUIT MEANS OF SAID SWITCH MEANS RESPECTIVELY TO SAID INPUT, OUTPUT AND CONTROL BUS MEANS OF SAID CHASSIS MEANS, SHIELD MEANS PROVIDED BETWEEN SAID INPUT AND OUTPUT BUS MEANS ON SAID CHASSIS MEANS AND BETWEEN SAID CHASSIS MEANS AND SAID SWITCH MEANS, AND MEANS INCLUDED IN SAID SWITCH MEANS TO CONNECT A SELECTED ONE OR ONES OF SAID INPUT BUS MEANS BY SAID CONTROL CIRCUIT MEANS TO SAID OUTPUT BUS MEANS.