Abstract: A system for continuously, automatically sensing the setting of operator controlled switches that denote: (1) the need for operator assistance [CALL]; and, (2) the operational status [STATUS] of a plurality of numerically controlled (N/C) machines is disclosed. The sensed CALL and STATUS information is transmitted, in a highly noise immune push-pull voltage manner, from the N/C machine locations (e.g., shop area) to a central processing unit (CPU) located in a control room. The CPU processes the received information and in accordance therewith transmits CALL control signals to one or more visual paging boards located in the shop area and to a status display board located in the control room. The status board displays, in real time, the STATUS information and CALL information, plus the elapsed time since a particular STATUS state started, or a particular CALL was made.