CallVolume hierarchy
===============

Service		org.ofono
Interface	org.ofono.CallVolume
Object path	[variable prefix]/{modem0,modem1,...}

Methods		dict GetProperties()

			Returns properties for the CallVolume object. See
			the properties section for available properties.

			Possible Errors: [service].Error.InvalidArguments

		void SetProperty(string property, variant value)

			Changes the value of the specified property. Only
			properties that are listed as readwrite are
			changeable. On success a PropertyChanged signal
			will be emitted.

			Possible Errors: [service].Error.InvalidArguments
					 [service].Error.DoesNotExist

Signals		PropertyChanged(string name, variant value)

			This signal indicates a changed value of the given
			property.

Properties	boolean Muted [readwrite]

			Boolean representing whether the microphone is muted.

		byte SpeakerVolume [readwrite]

			Represents the current volume of the speaker in
			percentage points.  Valid values are 0-100.

		byte MicrophoneVolume [readwrite]

			Represents the current volume of the microphone in
			percentage points.  Valid values are 0-100.