If the country merged into an existing country, the ISO 3166-1 alpha-2 code of this country is used (e.g., the German Democratic Republic merged into Germany, whose alpha-2 code is DE). If the country was divided into several parts, the special code HH is used to indicate that there is no single successor country (e.g., Czechoslovakia was Republic Airlines: REPUBLIC United States defunct; 1979–1986, merged with Northwest Airlines: RW RPA Republic Airways: BRICKYARD United States RH RPH Republic Express Airlines: PUBLIC EXPRESS Indonesia RBC Republicair: REPUBLICAIR Mexico RST Resort Air: RESORT AIR United States RUT Reut Airways: YADID Israel RGV RG Aviation: Venezuela 2014 But some of the most baffling expressions for many Olympics viewers have been the three-letter country abbreviations used by the Czech Republic DEN – Denmark ECU – Ecuador ERI – Eritrea
The two-letter country code format is the most widely used code format adopted by the majority of shipping carriers, brokers, and customs agencies. The codes standards are published by the International Organization for Standardization (ISO) and represent countries as well as territories.
Appendix 13 Country Codes for Customs Declaration Service has been updated to clarify the country code for Northern Ireland. 17 March 2023. Table 1 and Table 2 have been updated as follows: the
. 489 123 422 86 477 385 250 236

czech republic 2 letter country code