Abstract: A circular electrical connector of the type having mating plug and receptacle members, one of the members being spring mounted on a rigid rack and the other being mounted on heavy electronic equipment to be housed in the rack and electronically interconnected to external conductors through the connector, the members being equipped with horizontally positioned alignment support means which prevent mating engagement of the members until they are in proper axial alignment. The alignment means also support the weight of the equipment associated with the plug or receptacle member to prevent damage to the electrical contacts housed therein. The alignment means are located radially outwardly of the mating shells of the connector so as to permit connection of the receptacle member to a test connector having a standard coupling ring with helically shaped bayonet pin accommodating slots.