If you have a SMS mobile phone type ER USD and send it to,
                        Mobitel - 3040

                        Dialog - 3040

                        Celltel  - +94722403040

Similarly you are able to check any of the mostly used currency rates with Seylan Bank SMS Banking Facility.

If you need to verify the supported currencies, just send ER to the above mentioned number to receive the valid currency code list or refer User Guide.
(This service is available to anyone)