as is shown in fig2 the terminal block 40 are now fastened securely to the columns 46 with two screws located at the backplane cover area thereof next the proper i o unit 42 is engaged to the proper processor block 40 in a manner described earlier and as best seen in fig2 as was mentioned the conductive column 46 has connectors mounted into openings 74 formed on a connector wall thereof which provide power and signal connections respectively from the cabinet 44 to the i o module 42 of the block i o assembly 38 a pair of alignment pins 50 found on the back of the i o base or connector unit 40 when the unit 40 is mounted in the cabinet 44 the alignment pins 50 align the i o unit through an opening 52 formed therein this opening 52 matches an opening 55 found on the back of the i o module 42 which has individual dustered power and signal pins 57 59 which mate with an appropriate power and signal connections as will be explained later the power pins 57 on the i o module 42 will be electrically connected to the cabinet 44 before any signal pins 59 are connected to the cabinet by the proper mounting of the module 42 to the connector 40 into the i o block assembly 38 to provide a blind fit electrical connection of the i o module 38 which will also provide a sequential connection of the power signals 57 to the module before any signal 59 inputs thereto a unique power and signal holder assembly 170 is used to mount the i o block to the power.