Electrical reset to a SIM card
After applying power to the SIM card you must first supply a clock to the clk pin. Use something in the 3-3.5MHz range. Then pull the reset pin of the SIM card low for about 100ms, drive the reset pin high again, and listen to the I/O line for the ATR. It should come in at your clock frequency / 372 or something like that. The baud should be somewhere just under the 9600 range. I recommend scoping the line to find the exact rate.