PDP-5

The PDP-5 was built with DEC System Modules, the original line of transistorized logic modules sold by DEC. The supply voltages were +10 and -15 volts, with logic levels of -3 (logic 1) and 0 (logic 0). Logic was packaged on boards that were about 4.75 inches high with each card mounted in a metal frame with a 22 pin edge connector. Input output devices were connected to the daisy-chained I/O bus using military-style armored cables and connectors. Use of toggle switches (as opposed to slide switches) on the front panel was another vestige of military-style design.