en: for English version
  tc: for Tradition Chinese version
sc: for Simplfied Chinsed version
===== Update procedure ============
  Step1: Copy OS image (*.bin) to PC. 
  Step2: Run EShell on PC.
  Step3: Trun the rotary switch to the "3" position 
  and then restart the ViewPAC.
  Step4: Use EShell to select the ViewPAC.
  Step5: Use EShell to select the OS image.
  Step6: Run the ViewPAC Utility and save the configuration.
  Step7: Trun the rotary switch to the "0" position 
  and then restart the ViewPAC.
  Done.
For more details, please refer to the user manual.