#include <SoftwareSerial.h>

SoftwareSerial jdy31(10, 11);  // RX, TX

void setup() {
  Serial.begin(9600);
  jdy31.begin(9600);
}

void loop() {
  while (Serial.available()) {
    jdy31.write(Serial.read());
  }
  while (jdy31.available()) {
    Serial.write(jdy31.read());
  }
}