ISO7816-3 describes smart card electric signals and transmission protocols, the detail can refer to the spec, below are some examples about for better understanding about the spec, 1, ATR and Baud Rate my Singapore cash card ATR “3B2A00806524B0000200829000” 3B = TS – (H) LHHL HHH LLH sets up the direct convention 2A = T0, includes Y1 = bit8 to bit5 value as 2, bit wise as 0010, means only TB1 exists, and K as bit4 to bit1 value as 0x0A, history bytes length 0x0A.