If you don't have some HPA's to mute or don't need all the mute-outputs, you can use them as digital outputs as well. Therefore you have to open the top cover of sat-nms IO-FEP2's housing and put all the switches of corresponding outputs that you want to use this way, in the 'SOFTWARE CONTROLLED HPA MUTE' position. These switches are located between the DIP switches and are marked with 'HPA 1'...'HPA 10'. Don't exceed continuous current limit of 130mA and continuous voltage of 48V DC. Otherwise your sat-nms IO-FEP2 might be damaged. If you want to switch inductive loads, don`t forget to add a clamp diode to limit the spike voltages in the switching moment. Configuration of these outputs is described in chapter Installation Parameters .