There were cameras that include flash bulb sockets, intended for single bulb over cubes up to bars. All these cameras have incorparated a trigger devise. With the exception of Magicubes the triggering is by electric charge. These cameras do not have a electric switch controlling the trigger circuit of an electronic flashlight, nor that PC socket. Bridging the gap from electric charge to switching the flashlight is the concern of this tread.
With Magicubes the triggering is done mechanically. And by this, transfered by a simple key-switch, used for triggering an electronic flashlight in those adapters/flashlights you refer to.