Every U.S. dollar in the market has a 10- or 11-digit serial number that serves as a unique identifier for all existing United States paper currency. However, the ISO 4217 code is the only common identifier used internationally to distinguish world or foreign currencies. The International Organization for Standardization (ISO) establishes a unique three-letter code name that is specific to each country's currency. The first two letters of a currency's code corresponds to that of the country's top-level Internet domain. These currency codes are used in international airports, international banking and exchange rates, which you can search through free online websites.
Launch a Web browser.
Navigate to a search engine of your preference and search for "ISO currency codes by country." See Resources for a direct link.
Find a country from the list for which you wish to know the code and click "Search." The result shows a 3-letter code. For example, when searching for Japan's currency, the 3-letter code is JPY, for Japanese Yen.
Identify Taiwan's currency for example, by recognizing its ISO 4217 code. Select the country from the website's list and click "Search." The result shows "TWD," where "TW" corresponds to Taiwan's Internet domain suffix and the letter "D" corresponds to Taiwan's currency name "Dollar" (Taiwan Dollar).
Identify and recognize what each U.S. dollar bill's serial number represents. The serial number follows the following pattern: XX12345678X.
The first prefix letter corresponds to currency series. The second prefix letter corresponds to the Federal Reserve Bank where the bill was printed. For example "A" for "Boston," "G" for "Chicago," "B" for "New York" (see Resources). The 8-digit serial number + the suffix letter corresponds to the sequential order in which the bill was printed, within its series. For example, after the serial XX99999999D, the following serial within the series will be XX00000001E. The letter "O" is omitted from this cycle.