The Teletext project type is intended for working with SDH or Teletext subtitles and fully complies with the existing standards and best practices.
Teletext mode settings
The Teletext Language option can be used to warn you when you enter a symbol which is not part of the selected language's alphabet. If such characters exist they will be displayed as non-printable. The non-printable characters are replaced by a small rectangle symbol "□" in the text. If you are not sure about it then you can leave it to Not Specified to "allow" all characters and symbols to be inserted.
The Character Code Table option is available when Teletext Language is set to Not Specified and enables you to verify that only characters from the supported by EBU STL code tables are present in the file. All other characters will be displayed as non-printable "□" and will be caught by Check Subtitles. Please note that we don't recommend selecting Not Specified here - mixing characters from the different Code Tables will most likely cause problems later on when exporting EBU STL from your project because it forces you to select Character Code Table for the output file.
Use Teletext Level 1.5 checkbox to enable characters from G2 (supplementary) set to be used.
Please mind that Teletext Level 1.5 is a term introduced by ETSI EN 300 706 and doesn't have anything to do with EBU STL - it expands the supported by Teletext level 1 number of characters by introducing national sub-sets of characters and codes. The option is meant to verify if there are characters other than the allowed by the specific national sub-set. If such characters exist and this option is not turned on they will be displayed as non-printable.
The Teletext PAC/890 modes is best to be used when delivering your Teletext subtitles as either PAC or 890 file.