 // Copyright (C) 2016 Theodore C. Yapo
 
 #include <SoftwareSerial.h>
+#include <EEPROM.h>
 
 class DMM
 {

  while(!Serial){
    // busy wait
  }

  dmm.setPort(dmm_port, rx_pin);
  sample_pending = false;

void loop()
{
  if (Serial.available()){
    command = Serial.read();
    if ('I' == command){
      Serial.println(ID);
      return;
    }
    if ('W' == command){
      ID = Serial.parseInt();
      EEPROM.put(ID_location, ID);
      return;
    }
    sample_pending = true;
    dmm.sync();
  }

  if (dmm.poll() && sample_pending){
    sample_pending = false;
    switch(command){
    case 'n': // number only
    default:
      Serial.println(dmm.asciiValue());
