IpMultimediaSystem Hierarchy
============================

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

Methods		dict GetProperties()

			Returns all IpMultimediaSystem configuration 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.InvalidArguments
					 [service].Error.Failed

		void Register()

			Attempts to register to IMS. A successful method return
			indicates that the registration process could be
			initiated successfully. The actual registration state
			will be reflected by the 'Registered' property.

			Possible Errors: [service].Error.InProgress
					 [service].Error.NotImplemented

		void Unregister()

			Attempts to unregister from IMS. A successful method
			return indicates that the unregistration process could
			be initiated successfully. The actual unregistration
			state will be reflected by the 'Registered' property.

			Possible Errors: [service].Error.InProgress
					 [service].Error.NotImplemented

Signals		PropertyChanged(string property, variant value)

			This signal indicates a changed value of the given
			property.

Properties	boolean Registered [readonly]

			Contains the current IMS registration state.

		boolean VoiceCapable [readonly, optional]

			Boolean representing whether voice call transfer over
			RTP (IMS) is available.

		boolean SmsCapable [readonly, optional]

			Boolean representing whether SMS-over-IMS is available.
