It is the code used on the Internet. In the 1990's a 16-bit code was developed that will handle alphabets of many nations. These have a short standard name, a standard function plus a large number of non-standard applications. The original code was developed in the days of mechanical terminals such as Teletypes. These have been re-interpreted as cursor movements for CRT's.
Many computer systems use the control codes for special purposes.
This is not a character. It is transmitted thru an RS232 cable by dropping the DTR line to the signal ground, or thru a modem by ceasing to send the carrier frequency for a fixed length of time. A dot followed by white space is treated as a period. . On a network the special character take on yet more meanings. Proprietary networks often have a special 'escape' character as well.