Panasonic Toughbook CF-S9KWAZG1M Reference Manual page 118

Modem
118
NOTE
This function does not work when the computer is off or is in hibernation.
Connect the AC adaptor.
The screen remains dark after the computer resumes from sleep/ standby. The previous
Windows 7
Windows XP
screen display will be restored when you touch the keyboard, Touch Pad or screen.
The computer cannot resume if the telephone is not connected to the internal modem (e.g., you cannot use a PC Card
modem).
The computer needs some time to respond, so set the calling time longer than normal. If this is not possible on the
transmission side, reduce the number of rings before answering on the software that you are using to keep the
computer in idle waiting for the call.