The data is stored in the EEPROM and is coded for transmission. The user defines the coding format by means of a configuration register. The simplest method is NRZ (Not Return to Zero) coding. In fact, this is not a real coding method, instead, the data is transmitted as clocked out of the memory. This method is not recommended, however, since the average signal level is not DC-free and does not include any clock information in the bit stream. This is different for the two coding methods as shown in the diagrams in the center and below. Both schemes, Manchester or Biphase coding, are similar and always supply a slope, either at the beginning of the bit (Biphase) or in the middle of the bit (Manchester). This helps to simplify decoding. Moreover, the signal has no DC level. The disadvantage is that the required signal data rate is doubled.