Because of the dynamic nature of currency values, internet connectivity is required to retrieve up-to-date exchange rates.
By default, the Wolfram Language will automatically query FinancialData for the latest exchange rate information when doing arithmetic or unit conversion.
Wolfram Language code: UnitConvert[Quantity[19., "SwissFrancs"], "Euros"]Wolfram Language code: Quantity[1, "USDollars"] + Quantity[1, "Euros"]
When no internet connectivity is available, a String representing the exchange ratio is returned instead:
Wolfram Language code: Quantity[1, "USDollars"] + Quantity[1, "Euros"]Wolfram Language code: % /. "EUR/USD" -> 1.2
This is the same string that can be used to retrieve exchange rate information from FinancialData: