The Keep Port Option option is used only with Serial "solenoid-only" Cash Drawers which do not have an external power supply and are not connected through a Receipt printer.
See the manufacture's manual to learn how the Cash Drawer gets its power.
For some cash drawers that get their power from the serial port and not from an external power supply (e.g. APG Model 484A SerialPRO), it may be neccesary to enter CD in the COM Options parameters field (otherwise power is not made available through the port).
Note: If it is not certain that this setting is necessary for the Cash Drawer, leave it disabled.
Configuration Manager Contents