File Extension WTX File Format ASCII Text WTX stands for ASCII Text. This was last updated in March 2012 By Margaret Rouse Browse File Extensions Alphabetically: A B C D E F G H I J K L M N O P Q R S T U V W X Y Z # Ask a Question. Find an Answer. Ask your peers a question about this file extension. Ask a Question SNDDST output is ASCII SFTP How do you create a file containing Simplified Chinese characters (DBCS) and English in the same field on IBM iSeries IFS in UNICODE UTF-8 format?