Plug

A versatile plug which prevents signal and ground wires in pairs from being connected in reversed polarity; prevents short circuits occurring in adjacent lead wires; facilitates lead wire connecting operation; and which allows connection of lead wires of different types, has a pair of plug-side contact terminals contacted by a pair of apparatus-side terminals; a plug housing having an asymmetrical profile in conformity with a configuration of an apparatus-side connection recess; and a clamp detachably attached to each of the lead wires. By inserting the plug into the connection recess, the paired lead wires can be electrically connected to the paired apparatus-side terminals. Since the plug housing has an asymmetrical configuration, no reversed polarity connection occurs. A lead wire of any given thickness can be connected to the plug-side contact terminal by clamping with the clamp.