Connector assembly

A connector assembly, comprising

• a plug connector having a base body and at least one inserting portion extended from a front of the base body, the inserting portion having a substantially circular plug groove of which an inner wall has a portion formed with an anti-mismating portion of plane shape, the anti-mismating portion having a null terminal recess for receiving a null terminal;
• and
• a socket connector coupled with the plug connector, comprising:
• an insulating housing having at least one receiving groove at a front surface thereof and a substantially circular receiving portion surrounded by the receiving groove, the receiving portion having a portion formed with an anti-mismating face of plane shape, corresponding to the anti-mismating portion, with a null pin recess formed thereon;
• and
• a null pin received in the null pin recess having a resisting portion projecting outside the anti-mismating face for electrically connecting with the null terminal of the plug connector when the plug connector is inserted into the socket connector.