Call Meter hierarchy
===============
Service		org.ofono
Interface	org.ofono.CallMeter
Object path	[variable prefix]/{modem0,modem1,...}

Methods		dict GetProperties()

			Contains the properties for this object.

			Possible Errors: [service].Error.InProgress

		void SetProperty(string property, variant value,
				 string password)

			Sets the property to value specified in the
			call parameter.  The last parameter is used
			to pass the SIM PIN2 code which may be
			required by the SIM.

			Possible Errors: [service].Error.InProgress
					 [service].Error.NotImplemented
					 [service].Error.InvalidArguments
					 [service].Error.InvalidFormat
					 [service].Error.Failed

		void Reset(string password)

			Attempts to reset the Accumulated Call Meter.
			Reseting this value requires SIM PIN2, provided
			by the password parameter.

			Possible Errors: [service].Error.InProgress
					 [service].Error.NotImplemented
					 [service].Error.InvalidArguments
					 [service].Error.InvalidFormat
					 [service].Error.Failed

Signals		PropertyChanged(string property, variant value)

			Signal is emitted whenever a property has changed.
			The new value is passed as the signal argument.

		NearMaximumWarning()

			Emitted shortly before the ACM (Accumulated Call
			Meter) maximum values is reached.  The warning is
			issued approximately when 30 seconds call time
			remains or when starting a call with less than
			30 seconds remaining.

Properties	uint32 CallMeter [readonly]

			Contains the current call meter value from the ME.
			The values are in 24-bit range, counted in home
			units.

		uint32 AccumulatedCallMeter [readonly]

			Contains the Accumulated Call Meter (ACM) value
			from the SIM.  When the AccumulatedCallMeter
			value reaches AccumulatedCallMeterMaximum value,
			no further calls can be made until the ACM
			value is reset.  Reset is accomplished using
			the Reset() function.

			The values are in 24-bit range.

		uint32 AccumulatedCallMeterMaximum [readwrite]

			Contains the Accumulated Call Meter maximum value
			on reaching which, calls are prohibited.  This is
			effectively the maximum number of home units
			allowed to be consumed by subscriber.

			According to the GSM specification, setting the value
			to 0, turns off this feature.

			The values are in 24-bit range.

		double PricePerUnit [readwrite]

			Contains price-per-unit conversion value.  This
			information can be used to convert the home units
			into currency units.

		string Currency [readwrite]

			Contains three-character currency code.  This
			information can be used to convert the home
			units into currency units.