Abstract: By providing a plurality of input/output housings which are removably connected to a controller interconnecting duct, with each input/output housing accommodating a plurality of input/output modules that are quickly and easily removably connected thereto, an input/output assembly for a programmable controller is achieved capable of rapid field assembly and field dis-assembly for removal or replacement of any necessary parts. In the preferred embodiment, all connectors in the programmable controller assembly are solderless connections, thereby allowing complete removal and replacement of connectors in the field without soldering. Furthermore, the input/output modules are lightweight and easily handled for quick insertion or removal from the plugged-in housing connections.