Electronic apparatus having modular front and back functional units and electrical distribution unit including a fan therebetween

Modular electrical apparatus is provided which comprises a plurality of customer removable electrical devices 22 inserted in one end of a drawer type tubular chassis 10 and various field replaceable support units 44,46 mounted at the other end of the chassis. The devices and support units are all blind pluggable into a removable central electrical distribution unit which includes complementary connectors 52,54,56 on opposite sides and a set of electrical conductors for connecting the devices and units. Internal electrical connection of all the units in the drawer is via the electrical distribution unit and external electrical connection is made only to the outer end of the support units. Cooling fans for inducing an air flow through the tubular chassis to cool the devices and support units are mounted in the central electrical distribution unit. All the components can be removed for repair or replacement from either the front or rear entrance of the tubular chassis.