Intermec 6640 Technical Reference page 80

Toolkit for the 6640 Computer
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4-20 6640 Mobile Computer Technical Reference
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Setting Up the TDK CyberExpress 5600
The TDK CyberExpress 5600 modem driver runs from MS_DOS.
Do not attempt to run this driver from the Windows DOS box. You
must exit Windows and reboot the 6640 Computer to start from the
MS_DOS prompt.
Be sure to have the TDK Model DF5600 CyberExpress PC Modem
Card inserted in the 6640 Computer before continuing.
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