Method for transmitting an opening or a locking code and associated units

The opening code transmission method has an identification entered via a mobile radio network terminal (24) and received by a server (30), for authentication before transmission of an opening code back to the mobile radio network terminal, at which it is displayed to allow it to be entered in the coded lock (14) securing a bicycle (10). Also included are Independent claims for the following:- (a) a method for transmission of a closure code for a coded lock; (b) a terminal with a mobile radio interface and a control unit; (c) a server provided with a control unit.