Abstract: Transponder (2) associated with a communication system for various different applications having different security levels. This transponder includes means (18, 26, 40, R) allowing the maximum communication distance between the transponder and a reader (4) to be varied as a function of the application selected or activated. A code, which determines the opening or closing of the switch (40) is associated with each application. In a first group of embodiments, the equivalent impedance of the electronic unit associated with the antenna (6) is varied, whereas in another embodiment, the electric characteristics of the antenna itself are varied.