void Tone(char type_of_tone) {
  switch (type_of_tone) {
  case '0':
    Write_Treg(10);
    break;
  case '*':
    Write_Treg(11);
    break;
  case '#':
    Write_Treg(12);
    break;
  case 'D':
    Write_Treg(0);
    break;
  default:
    if (type_of_tone >= '1' && type_of_tone <= '9')
      Write_Treg(type_of_tone - 48);
    else
      Write_Treg(type_of_tone - 52);
  }
  Write_Creg(1);                                      // Tone on
  Delay(65);
  Write_Creg(0);                                      // Tone off
  Delay(65);
}