A call to SoftwareSerial(rxPin, txPin) creates a new SoftwareSerial object, whose name you need to provide as in the example below.
You need to call SoftwareSerial.begin() to enable communication.
rxPin: the pin on which to receive serial data
txPin: the pin on which to transmit serial data
#define rxPin 2 #define txPin 3 // set up a new serial port SoftwareSerial mySerial = SoftwareSerial(rxPin, txPin);