The Wiring SoftwareSerial library allows for easily reading and writing data to and from external machines through software serial ports. It allows two machines to communicate. Note: the SoftwareSerial class doesn´t have the available() method.

The serial port is a nine pin I/O port that exists on most PCs and can be emulated through USB on Macintosh and PCs with the Keyspan USB Serial adaptor.

SoftwareSerial
Wiring SoftwareSerial class (datatype).

begin()
Opens the serial port for reading and writing.

print()
Writes an int, float, byte, char, char[] or a number in decimal, hexadecimal, octal or binary base to the serial port.

println()
It works as the print method but prints a new line character at the end of each call.

read()
Returns a number between 0 and 255 for the next byte that's waiting in the buffer. Returns -1 if there is no byte.