Silicon Graphics Multibus "IP2" board -- Connectors and such

J1 -- 60 pins, 4 serial ports, mouse, conf0-7
J2 -- 40 pins - 32 bits of data to MT1 memory board
J3 -- 50 pins - 26 bits of address to MT1 memory board (and signals)
J4 -- 20 pins - to FPA board
J5 -- 34 pins - to "GE" board (Geometry Engine)