Method for checking communication link between two switches of switch mechanism and corresponding checking device

The invention relates to a method for checking a communication link (K1) between two switches (CB1 and CB3). The switches are directly connected in series; each of the switches (CB1 and CB3) is used for checking whether electric energy flowing through a contact element meets a rated condition; a tripping unit ETU of the upstream switch (CB1) is provided with energy (EQP1); the energy and a switch device (SO) of the tripping unit ETU of the downstream switch (CB3) form a circuit through the communication link (K1), so that a signal (S) with a voltage change form and/or a current change form is generated; the switch device (SO) of the downstream switch (CB3) is used for switching on or switching off the circuit. In order to realize a technically simple method and a technically simple device, the method provided by the invention has the advantages that on the premise that a condition cannot be met, within a rated time interval, (a) the upstream switch awaits for the signal (S), (b) the downstream switch generates the signal (S), and (c) if the upstream switch (CB1) detects the signal (S) within the time interval, the communication link (K1) is normal.