A connector (1) comprising a least a housing (10) with a least one aperture (12), at least two terminals each being inserted into one of the aperture (12) and at least one locking device (30) for insertion into an opening (11) of the housing (10) for locking at least one of the terminals in an aperture (12), permits an easy control of the connection of the terminals, if the locking device (30) comprises at least two contact pads (36), each contact pad connecting one of the at least two terminals (50), and if the locking device (30) supports a signaling circuit, being connected to the contact pads (36).