Circuit arrangement that functions as an interface between a sim card and gsm modem

摘要

The present disclosure relates to a circuit arrangement and a method for defining the signal direction in a data line between the interfaces of a SIM card and a GSM modem, without a control signal for the direction of data and without remote access. According to the disclosure, the transmission direction of the data signals is detected and as a result only one direction is permitted for the transmission, whilst detection in the opposite direction is simultaneously blocked.