Beijer Electronics QTERM®-A12 - Manual (Page 12)

Primary Serial Port Connector for Power Input Applying Power
6 QTERM-A12 Terminal
lation between signal common and earth ground, care must be taken when connections are
made to the terminal. For example, a power supply with isolation between its signal common
and earth ground must be used. Also, plugging in a serial cable or a USB cable may connect
signal common and earth ground.
The serial cable shield or the USB shield may be connected to earth ground at the host. The
serial cable or the USB shield, in turn, may also be connected to signal common.
3.2 Primary Serial Port Connector for Power Input
Power can be supplied to the terminal through pin 9 and ground return through pin 5 of the
COM1 serial port connector.
3.3 Terminal Strip for Power Input
The 3-pin terminal strip is used to provide input voltage and ground to the terminal. The termi-
nal strip provides a chassis ground connection. The chassis ground pin is isolated from the sys-
tem ground of the terminal.
W ARNING
Although the terminal includes protection circuitry to prevent power supply contention,
power should not be connected to the 3-pin terminal strip or the RJ45 PoE interface while
power is applied to the DB9 connector.
W ARNING
Although the terminal includes protection circuitry to prevent power supply contention,
power should not be connected to the DB9 connector or the RJ45 PoE interface while power
is applied to the 3-pin terminal strip.
W ARNING
QTERM-A12 power must come from an SELV (Safety Extra Low Voltage) power source
and should have a current limit on its output of 5 Amperes. It must provide a minimum of 10
volts DC power and be limited to a maximum of 32 volts DC. Limiting may be inherent to
the supply or may be provided by supplementary overcurrent devices. If the QTERM-A12
does not respond or exhibits abnormal behavior on power up, disconnect power and contact
Beijer Electronics for technical support.