Positive and ground apply input discrete signals avia.

[Elena_T]

Здравствуйте!
Помогите, пожалуйста, разобраться с терминами "Positive apply inputs" и "Ground apply inputs" в следующем контексте:

The EHSI interfaces to positive and ground apply input discrete signals as shown below. Ground applied input
states may be “GND” or “Open” where “GND” is less than 2.5 Vdc and where “Open” is a resistance greater
than 100 KΩ. Current flow through the input wire for ground apply aircraft inputs in the active state will be
nominally 5 ma. Positive Apply inputs require a voltage > 9 Vdc for the active state and ≤ +2.5 Vdc for the
inactive state. Input impedance for the positive apply inputs is approximately 5.6 KΩ.

Перевожу руководство по эксплуатации электронного индикатора плановой навигационной обстановки

[Elena_T]

Ну неужели никто не сможет помочь?(((