Texas Instruments 4000M - Manual (Page 201)

5. In modes that support simultaneous display on the
LCD and the CRT , switch to simultaneous display by
double-clicking the SimulScan icon in the Windows
Notebook Group menu or by typing
SIM
at the MS-DOS C:\ prompt and pressing ENTER.
For usage information, refer to the external monitor
documentation.
External Monitor
TravelMate Options 11-15