Source : Free On-Line Dictionary of Computing

TK-90X
     
         A Brazilian {clone}, manufactured by {Micro
        Digital}, of the British {Sinclair Research} {ZX Spectrum}
        {8-bit} {microcomputer}.  It differed from the standard
        Spectrum by adding an {Interface 2}-compatible {joystick}
        {interface}, and extra {BASIC} commands to aid {programming}
        and {graphics}-editing.  Because of these differences, it was
        slightly incompatible with the standard Spectrum.
     
        A later model, the TK-95, which boasted an improved keyboard
        (similar to the {Commodore 64}'s) and a more compatible {ROM},
        was little more than a {Timex} {TC2048} (another Spectrum
        clone) in disguise.
     
        {comp.sys.sinclair FAQ
        (http://www.kendalls.demon.co.uk/cssfaq/)}.
     
        ["comp.sys.sinclair FAQ", D Burke M Fayzullin P Kendall et al,
        pub. Philip Kendall 1998]
     
        (1998-11-09)