Panasonic CF-19CHGACJM - Toughbook 19 Touchscreen PC Version Reference Manual page 127

Technical Information
Serial Devices
The COM ports of the computer are assigned as below.
COM1 : Serial Port A
COM2 : Serial Port B (Port replicator
*2
COM3 : GPS
*2
Optional
If you change the assignment, the serial devices may not work properly.
*2 *2
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