A bayonet-type locking and unlocking system for a circular connector with audible indicator of locking, including: a socket including at least one unlocking ramp, a locking ring including at least one locking ramp in which the lug of the socket slides in translation, a locking piece including a blocking tooth, an unblocking lug, and a guideway, the system including a locking position in which the blocking tooth is positioned in the guide slot blocking the position of the lug of the socket in the circular part of the locking ramp.