Hitachi HILS86204 User Manual page 16

4) RS232C Connection
HITACHI Models supports two connection methods : RS232C and LAN standard.
Simultaneous connection of two standards is not supported.
Please select RS232C cable or LAN connection.
※ Note
How to select RS232C On/Off switch
RJ45(↑), RS232C(↓)
The RS232C port will not work once RJ45 is being used.
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