STEVEN G LANDRY
Radio and Television Technicians in Hudson, NH

4591967, May 27, 1986

Jul 25, 1985

6/758840

Donald A. Mattes - Lincoln MA
Steven G. Landry - Litchfield NH
James M. Kendall - Nashua NH

Andover Controls Corporation - Andover MA

G06F 1546, G06F 1516

364132

Master units and slave units are preferably housed in identical housings. Each master unit comprises a Central Intelligence Unit (CIU) which in turn comprises a drum processor and a communications processor, and an Input/Output Unit (IOU) having input terminals and relays for connection to external devices. Each slave unit comprises an IOU. Each IOU is connected to its CIU through a Local bus (L-bus). Up to sixteen IOU's may be controlled by a single CIU. Up to 16 master units may be connected together by means of console bus (C-bus) and a data exchange bus (X-bus), in which case each master unit is given control of specified "X" variables for update. Each "X" variable has a specific time slot on the X-bus and all "X" variables are stored on an X-drum at each master unit. The C-bus may be connected to a computer terminal at each master for programming of all CIU's, or to computer devices, or to long distance communication lines. Each IOU monitors continuously 32 identical input ports and maintains in a table the voltage at that port, whether the voltage has gone up or down through preselected voltages and the number of times this has happened since the last interrogation by its CIU on the L-bus.

D276152, Oct 30, 1984

Jan 20, 1982

6/341125

Charles M. Ault - Winchester MA
Steven G. Landry - Litchfield NH

Andover Controls Corporation - Andover MA

D13 35