Attributes . 3mA without Zone Doubling, 2.4mA with Zone Doubling using a 2.2K Ohm end-of-line resistor (Model EOL2.2K); 5mA for 2-wire smoke-detector zones; 1.4 mA using a 3.9K Ohm resistor (Model EOL 3.9K) with Zone Doubling . Names