A balise suitable to be arranged fixedly between rails of a railway track to communicate wirelessly with a vehicle communication device of a railway vehicle on the railway track, the balise comprising: a receiver having a receiver loop and being configured to receive from the vehicle communication device via the receiver loop a receive signal having first receive signal characteristics or second receive signal characteristics different to said first receive signal characteristics; the receiver having energy storage circuitry configured to tap energy from the receive signal for powering the balise and having a detector configured to provide an indication of whether the receive signal has the first receive signal characteristics or the second receive signal characteristics; a transmitter having a transmitter loop and being configured to transmit to the vehicle communication device via the transmitter loop a first telegram signal in a Frequency Shift Keying, FSK, operational mode according to the Eurobalise specification, or a second telegram signal in an Amplitude Shift Keying, ASK, operational mode according to the KER/KVB specification; characterized by said balise further comprising: the transmitter having a variable capacitance , which forms a resonant circuit together with the transmitter loop , an active feedback circuitry having an input and an output both coupled to the resonant circuit , and a switch to selectively short-circuit the input of the active feedback circuitry to render the active feedback circuitry inactive; a controller configured to cause variation of the variable capacitance of the transmitter to attain the FSK operational mode and to cause the switch to short-circuit the input of the active feedback circuitry to attain the ASK operational mode. a receiver having a receiver loop and being configured to receive from the vehicle communication device via the receiver loop a receive signal having first receive signal characteristics or second receive signal characteristics different to said first receive signal characteristics; the receiver having energy storage circuitry configured to tap energy from the receive signal for powering the balise and having a detector configured to provide an indication of whether the receive signal has the first receive signal characteristics or the second receive signal characteristics; a transmitter having a transmitter loop and being configured to transmit to the vehicle communication device via the transmitter loop a first telegram signal in a Frequency Shift Keying, FSK, operational mode according to the Eurobalise specification, or a second telegram signal in an Amplitude Shift Keying, ASK, operational mode according to the KER/KVB specification; characterized by said balise further comprising: the transmitter having a variable capacitance , which forms a resonant circuit together with the transmitter loop , an active feedback circuitry having an input and an output both coupled to the resonant circuit , and a switch to selectively short-circuit the input of the active feedback circuitry to render the active feedback circuitry inactive; a controller configured to cause variation of the variable capacitance of the transmitter to attain the FSK operational mode and to cause the switch to short-circuit the input of the active feedback circuitry to attain the ASK operational mode. the transmitter having a variable capacitance , which forms a resonant circuit together with the transmitter loop , an active feedback circuitry having an input and an output both coupled to the resonant circuit , and a switch to selectively short-circuit the input of the active feedback circuitry to render the active feedback circuitry inactive; a controller configured to cause variation of the variable capacitance of the transmitter to attain the FSK operational mode and to cause the switch to short-circuit the input of the active feedback circuitry to attain the ASK operational mode. <EOS>