The IDN (Internationalized Domain Name) defines a domain where diacritical national characters specific to the language are used.
What is an IDN?
IDNs can contain language specific characters. In the case of Polish you can use all letters of the alphabet. For example, instead of the domain wielbłądy.org you can have the domain wielblady.org (Unicode format), the computer will understand this name as xn--wielbdy-t4a26c.org (ASCII format). If you want to know more, we recommend reading our compendium about domains.
How can I convert an IDN domain name to ASCII?
In order to convert an IDN domain name to ASCII you can use, for example Polish Domain Registry website. At the bottom of page there is a section "IDN/ASCII Translator with Domain Browser" with a field to complete. With this tool you can translate a domain with national characters into its ASCII form, and vice versa.