Abstract: An improved electrical connector assembly (for transmitting biopotential signals) comprises a main terminal connector associated with a master cable connectable to the signal processing apparatus and at least one plug associated with a single cable connectable to an biopotential electrode for sensing the biopotential signal of increase. The connector comprises a cavity defining a plurality of contiguous passageways each structured so as to receive the plug in only one direction to provide proper polarization. The design of the plug and the passageways, a color coding provided on the housing and the plug, the provision of an automatic interlocking mechanism allowing each plug to be inserted in any passageway and automatically locked in place, provides for easy, reliable and quick connections to be made. The preferred connector is designed to be easily cleaned such as by immersing it in a cleaning fluid, and the connecting pins are provided in a protective manner in the connector.