This object is a backplane which accepts 80 DYSEAC pluggable logic modules organized in 4 rows. Two plenums between the rows supply cooling air to a hole near the base of each module. Module positions are color coded. Each module plugs into a socket with 4 rows of pins. On the back of the backplane are 2 rectangular connectors with signal name labels organized into 2 rows. At each end are heavy duty connectors which are wired to power busses on the backplane. This backplane is labled as "G".