Data transmission method and apparatus therefor

A data transmission and receiving method performed by transmitting and receiving devices, comprising the steps of:

• (a) transmitting first data by the transmitting device;
• (b) changing a level of a data transmission signal, by the transmitting device, after the first data is transmitted;
• (c) reading, by the receiving device, the transmitted first data after the change in the level of the data transmission signal is detected by the receiving device;
• (d) changing a level of a data reception signal, by the receiving device, after the transmitted first data is read;
• (e) transmitting second data, by the transmitting device, after the change in the level of the data reception signal is detected by the transmitting device;
• (f) changing the level of the data transmission signal, by the transmitting device, after the second data is transmitted;
• (g) reading, by the receiving device, the transmitted second data after the change in the level of the data transmission signal is detected by the receiving device;
• and
• (h) changing the level of the data reception signal, by the receiving device, after the transmitted second data is read.

A data transmitting and receiving system, comprising:

• transmitting means for transmitting the data;
• transmitting signal means, coupled to said transmitting means, for producing and alternating between two levels of a data transmission signal after each transmission of data;
• transmission signal detecting means, coupled to said transmitting signal means, for detecting the change in level of the data transmission signal;
• reading means, coupled to said transmitting means and said transmission signal detecting means, for reading the transmitted data after the change in level of the data transmission signal is detected;
• reception signal means, coupled to said reading means, for producing and alternating between two levels of a data reception signal after reading and after each detection of change in level of the data transmission signal;
• and
• reception signal detecting means, coupled to said reception signal means and said transmitting means, for detecting the changes in level of the data reception signal and said transmitting means transmitting additional data after the change in level of the data reception signal is detected.