Juniper mesa 2 Owner's Manual page 46

The options can be edited to suit your application:
Enable RS-232 port: When it is unchecked, it powers
„
down. When this option is checked, it powers up the RS-
232 hardware. It then displays the assigned COM port
number.
NOTE: If you do not have a device plugged into the RS-
232 port, the port pins corrode more quickly when left
powered up. Use the setting to power down when it is not
going to be used.
NOTE: Power consumption during sleep is higher when the
RS-232 hardware is powered up.
Configure RS-232 Signals: Select Always enabled to
„
have the RS-232 output signals driving and input signals
enabled when the Mesa 2 is running or in sleep mode.
Select Disabled during sleep to have the RS-232 output
and input signals disabled automatically when the
tablet is in sleep mode. If your app and/or RS-232 device
experiences communication failures when tablet enters
or exits sleep mode, then do not use this option.
Configure pin 9 as input or power supply: Pin 9 is the Ring-
In signal input. It is rarely used by devices anymore and
has become a popular pin to provide a power source to
an RS-232 device.
Select Input if your device uses Ring-In signal or if it does
not need to be powered from the RS-232 port.
Select Power supply enabled to make pin 9 a power
supply to be used by the RS-232 device. The power supply
is enabled automatically without needing any interaction
with the COM port. Depending on the model, the power
supply supplies either 5 VDC or 12 VDC.
Select DTR enables power supply to make pin 9 a power
„
supply (5 VDC or 12 VDC depending on model). The
power supply remains off until the user application opens
the COM port and asserts the DTR signal. When the DTR
signal de-asserts, the power supply turns off again.
Check Disable power supply during sleep to cause the
„
power supply to automatically turn off when the tablet
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Mesa 2 Rugged Tablet Owner's Manual