US 7,627,345 B2Granted

Circuit arrangement that functions as an interface between a SIM card and GSM modem

AssigneeCinterion Wireless Modules GmbH

InventorsHans-Jürgen Neuhaus, Marten Petschke

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Abstract

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.

Claims18

Dependent claims

An interface apparatus between a SIM card and a GSM modem, comprising:

a bidirectional data line connecting a card data input/output of the SIM card to a modem data input/output of the GSM modem;
a branching area within said bidirectional line, wherein said branching area comprises a parallel first and second unidirectional data lines, each respectively comprising a first and a second opposite direction blocking element, such that the first unidirectional data line can pass data signals only in the direction from the SIM card to the GSM modem and the second unidirectional data line can pass data signals only in the opposite direction;
a respective first and second data signal blocking device operatively coupled to the first and the second unidirectional data line, wherein the first and second data signal blocking device can in each case block data signals in the forward direction;
a first and a second data signal direction identification device operatively coupled to the card and modem data input/output;
wherein the respective first or second data signal direction identification device is operatively coupled to the respective second or first data signal direction identification device via a respective second or first direction identification blocking device;
and
wherein data signals are transmitted in only one direction so that the transmission of data signals from the SIM card is identified by the first data signal direction identification device, which then uses the second direction identification blocking device to block the second data signal direction identification device in the direction from the GSM modem to the SIM card, and the first data signal blocking device blocks the data line in the direction from the GSM modem to the SIM card;
or
wherein data signals transmitted from the GSM modem is identified by the second data signal direction identification device, which then uses the first direction identification blocking device to block the first data signal direction identification device in the direction from the SIM card to the GSM modem, and uses the second data signal blocking device to block the data line in the direction from the SIM card to the GSM modem.

6 more elements

Dependencies are inferred from the claim text.

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Abstract

An interface apparatus between a SIM card and a GSM modem, comprising:

a bidirectional data line connecting a card data input/output of the SIM card to a modem data input/output of the GSM modem;
a branching area within said bidirectional line, wherein said branching area comprises a parallel first and second unidirectional data lines, each respectively comprising a first and a second opposite direction blocking element, such that the first unidirectional data line can pass data signals only in the direction from the SIM card to the GSM modem and the second unidirectional data line can pass data signals only in the opposite direction;
a respective first and second data signal blocking device operatively coupled to the first and the second unidirectional data line, wherein the first and second data signal blocking device can in each case block data signals in the forward direction;
a first and a second data signal direction identification device operatively coupled to the card and modem data input/output;
wherein the respective first or second data signal direction identification device is operatively coupled to the respective second or first data signal direction identification device via a respective second or first direction identification blocking device;
and
wherein data signals are transmitted in only one direction so that the transmission of data signals from the SIM card is identified by the first data signal direction identification device, which then uses the second direction identification blocking device to block the second data signal direction identification device in the direction from the GSM modem to the SIM card, and the first data signal blocking device blocks the data line in the direction from the GSM modem to the SIM card;
or
wherein data signals transmitted from the GSM modem is identified by the second data signal direction identification device, which then uses the first direction identification blocking device to block the first data signal direction identification device in the direction from the SIM card to the GSM modem, and uses the second data signal blocking device to block the data line in the direction from the SIM card to the GSM modem.

6 more elements