A modular mounting for a computer motherboard. An outer cabinet is designed to provide a protective enclosure for electrical components, and designed to permit throughhole drilling to facilitate mounting on a wall while avoiding disturbance of contents to be mounted within the outer cabinet. A subpanel plate is designed to detachably and securely attach a computer motherboard and cage assembly, and designed to removably mount the motherboard and cage assembly within the outer cabinet as a modular component, mounting of the motherboard and cage assembly being independent of power supply and nonvolatile storage. An inner cage is designed to protectably mount and enclose a computer motherboard and heat sink, and mount to the subpanel plate. A multipole switch may have a set of contacts for each conductor of a network cable entering the outer cabinet, one throw of the switch connecting all conductors of the cable, another throw of the switch disconnecting all contacts of the cable.