   source = scpi_register_command(ctx.command_tree, SCPI_CL_CHILD, "SOURCE", 6, "SOUR", 4, NULL);
   scpi_register_command(source, SCPI_CL_CHILD, "FREQUENCY", 9, "FREQ", 4, set_frequency);
   scpi_register_command(source, SCPI_CL_CHILD, "FREQUENCY?", 10, "FREQ?", 5, get_frequency);
+  
+  frequency = 1e3;
 
   Serial.begin(9600);
   dds.begin();

    args = args->next;
  }

  output_numeric = scpi_parse_numeric(args->value, args->length, 0, 0, 25e6);
  if(output_numeric.length == 0 ||
    (output_numeric.length == 2 && output_numeric.unit[0] == 'H' && output_numeric.unit[1] == 'Z'))
  {
    dds.setFrequencyHz(0, (unsigned long)constrain(output_numeric.value, 0, 25e6));
  }
  else
  {

  char line_buffer[256];
  unsigned char read_length;
  
  dds.setFrequencyHz(0, 1000);
  
  dds.selectFrequencyRegister(0);
  
  dds.enable();
