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.

		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.InProgress
					 [service].Error.NotImplemented
					 [service].Error.InvalidArguments
					 [service].Error.InvalidFormat
					 [service].Error.Failed

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.