The sim card interfaces consists of the series of the impedance matching circuits as we see there are six pins and there are eight pins some of the sim’s. The termination resistor has a value of 1- 10k ohm for data line & reset line and here we have 1-2k ohm for the clk line.we here build the circuits as per the pin requirements as we see i have connected the crystal oscillator for the clk pin and the requirement is calculated Vsim pin is connected to the DTR of rs232 terminal, then the clk is to the crystal oscillator,these data lines simdata and Vsim terminalthe the RTS of rs232 is connected to the simrst pin ,the circuit shows almost all the pins covered this is done without using any other ic. The chip is all integrated to the single cable usb line which has max 232 which converts the TTL logic to the computer logic.