An auxiliary module for an electrical switching device , the electrical switching device comprising at least one input , an output , a first housing and a switching module configured to switch between a first configuration in which the switching module allows electrical current to flow between the input and the output and a second configuration in which the switching module prevents current from flowing between the input and the output , the first housing delimiting a chamber accommodating the switching module , the first housing further delimiting a slot for receiving the auxiliary module , the slot comprising at least one signalling member configured for transmitting to the auxiliary module a first item of information relating to a state of the electrical switching device when the auxiliary module is received in the slot , the auxiliary module comprising a controller configured to generate a message containing second information representative of the first transmitted information, and a radio frequency communication module configured to transmit the message, via a radio frequency data link, to a device remote from the electrical switching device , the auxiliary module being characterised in that it comprises a second housing , a first printed circuit board , a second printed circuit board , and a movable element , the second housing delimiting a chamber accommodating the first board and the second board , the first printed circuit board carrying the controller and extending in a first plane, the second printed circuit board being connected to the first printed circuit board and extending from the first printed circuit board in a direction perpendicular to the first plane, the second printed circuit board carrying an electrical circuit connected to the controller , the mobile element being configured so that it can be moved in translation by the signalling member in a direction of translation (X) between a first position in which the electrical circuit is open and a second position in which the mobile element closes the electrical circuit, the state of the switching device being indicated by the open or closed state of said electrical circuit. the auxiliary module comprising a controller configured to generate a message containing second information representative of the first transmitted information, and a radio frequency communication module configured to transmit the message, via a radio frequency data link, to a device remote from the electrical switching device , the auxiliary module being characterised in that it comprises a second housing , a first printed circuit board , a second printed circuit board , and a movable element , the second housing delimiting a chamber accommodating the first board and the second board , the first printed circuit board carrying the controller and extending in a first plane, the second printed circuit board being connected to the first printed circuit board and extending from the first printed circuit board in a direction perpendicular to the first plane, the second printed circuit board carrying an electrical circuit connected to the controller , the mobile element being configured so that it can be moved in translation by the signalling member in a direction of translation (X) between a first position in which the electrical circuit is open and a second position in which the mobile element closes the electrical circuit, the state of the switching device being indicated by the open or closed state of said electrical circuit. <EOS>