A smart card reader (1) capable of transmitting a power signal to a smart card (2) to determine a duration WT called Waiting Time in keeping with the standard ISO 7816 and sending commands to said smart card (2), the reader (1) comprising a detector for detecting a malfunctioning condition of the smart card (2) and being configured to cut said power signal when the malfunctioning condition is fulfilled. This reader is remarkable in that said malfunctioning condition is different to reaching, by a counter configured to be incremented with the time from the sending of a command to the smart card (2), of a value corresponding to the duration WT elapsed from the sending of the command or reinitialisation of the counter in response to the receipt of a protocol message of the smart card (2).