Read:
T G C 
C T G 
G C T 
Data transmission fine...

Read:
A G C 
C T G 
G C T 
Error in pos: (0,0) ... corrected, new code:
T G C 
C T G 
G C T 

Read:
A C C 
C T G 
G C T 
Can't correct more than one error

Read:
A C C 
G A G 
G C T 
Data transmission fine...

Read:
A C C 
G A G 
A C T 
Check code error at position (2, 0)