Last Revised
AST RESEARCH, INC.        TECHNICAL BULLETIN # 1742          07/22/97 
 
 
 
TITLE:  Simultaneous Display Functionality
 
 
ISSUE 
 
   When using external desktop projectors, the Ascentia P notebook 
   may exhibit the following problems: 
   
   1. With the Xerox DP2810 projector in either Liquid 
      Crystal Display (LCD) or CRT display mode, the 
      display on the internal LCD and external projector    
      work well respectively. However, in simultaneous    
      (LCD+CRT) display mode, both the LCD and the projector 
      display shows flickering.
   
   2. In simultaneous display mode, only the internal LCD 
      display works on the Sharp XG5800E projector.
      There is no display on the external projector.
   
   This issue affects all Ascentia P systems.    

 
BACKGROUND 
 
   These problems are most commonly encountered when the high 
   resolution (800x600 or even 1024x768) notebooks used with 
   monitors, video projectors, or LCD display panels that, 
   typically, only support a resolution of 640x480. Either the panel 
   displays nothing, or it displays a scrambled or skewed picture.
   
   Due to current technology limitations in portable graphic 
   controllers, and the timing requirements of various display 
   devices, AST cannot guarantee nor support full simultaneous 
   display functionality in all environments.
   
   This issue may also affect all portable systems on the market 
   today.    

 
ACTION 
 
   In order to make use of simultaneous display mode with Ascentia P 
   notebooks that come with high resolution screens, your external 
   display device must support the native resolution of your 
   notebook's screen. In other words, to have simultaneous display 
   on Ascentia P systems with a native resolution of 800x600, an 
   external display device with a resolution up to 800x600 must be 
   used.    

 
NOTES 
 
   N/A    

 
TAN PRJ 3615AN 
 
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