anchor.diff:  
   	var/on = 1
   	var/alert = 0
  -
  +	var/previousPressure
   
   obj/machinery/airlock_sensor/update_icon()
   	if(on)
  
positive.code: 
  			radio_connection.post_signal(src, signal, range = AIRLOCK_CONTROL_RANGE, filter = RADIO_AIRLOCK)
  	return
  		
  obj/machinery/door/airlock/proc/set_frequency(new_frequency)
  	radio_controller.remove_object(src, frequency)
  	if(new_frequency)
  
negative.code: 
  obj/machinery/airlock_sensor/New()
  	..()
  	update_icon()
  
  	if(radio_controller)
  		set_frequency(frequency)
  