Method for selecting symbols and data communication system using the selected symbols

A method of selecting a symbol, the method comprising:

• inputting a first condition, a second condition, a third condition, and a fourth condition to be identified in a program designed to select a symbol, wherein:
• the first condition is that the sum of the difference values based on the common voltage of all transmission lines equals 0V;
• the second condition is that adjacent transmission lines must have different signal levels;
• the third condition is that the elements must convert into differential signals through a comparison of signal levels between adjacent transmission lines and must have different differential signals;
• and
• the fourth condition is that the elements must convert into differential signals through a comparison of signal levels between non-adjacent transmission lines and must have different differential signals;
• inputting the number of transmission lines, the number of signal levels, and determining the type of signal levels;
• initializing a candidate list and a resultant list;
• inputting the number of transmission lines, the number of signal levels, and the number of all possible configurations of the transmission lines into the candidate list, taking into account the types of signal levels;
• extracting one element from the candidate list;
• inputting the extracted element into the resultant list when the extracted element satisfies the first condition and then repeating the extracting one element;
• inputting the extracted element into the resultant list when the extracted element satisfies the second condition and then repeating the extracting one element;
• inputting the extracted element into the resultant list when the extracted element satisfies the third condition and then repeating the extracting one element;
• inputting the extracted element into the resultant list when the extracted element satisfies the fourth condition and then repeating the extracting one element;
• and
• outputting the resultant list when there are no remaining elements in the candidate list.