According to the BACnet protocol documentation:

Defines a standardized object whose properties represent the externally visible characteristics of a binary input. A "binary input" is a physical device or hardware input that can be in only one of two distinct states. In this description, those states are referred to as ACTIVE and INACTIVE. A typical use of a binary input is to indicate whether a particular piece of mechanical equipment, such as a fan or pump, is running or idle. The state ACTIVE corresponds to the situation when the equipment is on or running, and INACTIVE corresponds to the situation when the equipment is off or idle.

Objects of type binaryInput have the following properties:

•ackedTransitions

•activeText

•alarmValue

•changeOfStateCount

•changeOfStateTime

•description

•deviceType

•elapsedActiveTime

•eventAlgorithmInhibit

•eventAlgorithmInhibitRef

•eventDetectionEnable

•eventEnable

•eventMessageTexts

•eventMessageTextsConfig

•eventState

•eventTimeStamps

•inactiveText

•interfaceValue

•notificationClass

•notifyType

•objectIdentifier

•objectName

•objectType

•outOfService

•polarity

•presentValue

•profileLocation

•profileName

•propertyList

•reliability

•reliabilityEvaluationInhibit

•statusFlags

•tags

•timeDelay

•timeDelayNormal

•timeOfActiveTimeReset

•timeOfStateCountReset