#include <SoftwareSerial.h>

SoftwareSerial myserial4(10, 11);  // RX, TX


void setup() {
  Serial.begin(9600);
  myserial4.begin(4800);
}

String current_msg = "";

void loop() {
  while (myserial4.available() > 0) {
    char c = myserial4.read();
    Serial.write(c);
  }

  while (Serial.available() > 0) {
    char c = Serial.read();

    if (c == '\n') {
      Serial.print("me: ");
      Serial.println(current_msg);
      current_msg = "";
    } else {
      current_msg += c;
    }
    myserial4.write(c);
  }
}