Abstract: A unit of a system for controlling the operating functions of a cycle is able to co-operate functionally with at least one complementary unit by at least one electrical connection. At least one of either the unit and the complementary unit is configured to be selectively removable from the cycle, so that the electrical connection is an electrical connection that can be decoupled by leaving exposed on the unit at least one distal contact part. Associated to the at least one electrical connection is a switch, which can be selectively actuated for electrically insulating the exposed distal contact part from the unit.