Source : Free On-Line Dictionary of Computing

BinHex
     
         A {Macintosh} format for representing a {binary
        file} using only {printable character}s.  The file is
        converted to lines of letters, numbers and punctuation.
        Because BinHex files are simply text they can be sent through
        most {electronic mail} systems and stored on most computers.
        However the conversion to text makes the file larger, so it
        takes longer to transmit a file in BinHex format than if the
        file was represented some other way.
     
        {Filename extension}: .hqx.
     
        See also {BinHex 4.0}, {uuencode}.
     
        [Encoding algorithm?]
     
        (1994-11-30)