According to the BACnet protocol documentation:

Defines a standardized object whose properties represent the externally visible characteristics of a countdown timer. The Timer object provides a network-visible view of selected parameters of a countdown timer. The operating state of the timer may be viewed and controlled through these properties.

Objects of type timer have the following properties:

•ackedTransitions

•alarmValues

•defaultTimeout

•description

•eventAlgorithmInhibit

•eventAlgorithmInhibitRef

•eventDetectionEnable

•eventEnable

•eventMessageTexts

•eventMessageTextsConfig

•eventState

•eventTimeStamps

•expirationTime

•initialTimeout

•lastStateChange

•listOfObjectPropertyReferences

•maxPresValue

•minPresValue

•notificationClass

•notifyType

•objectIdentifier

•objectName

•objectType

•outOfService

•presentValue

•priorityForWriting

•profileLocation

•profileName

•propertyList

•reliability

•reliabilityEvaluationInhibit

•resolution

•stateChangeValues

•statusFlags

•tags

•timeDelay

•timeDelayNormal

•timerRunning

•timerState

•updateTime