3Com 7750 Series User Manual - Page 7

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3Com 7750 Series User Manual
PoE Power Rack Installation Guide
Likewise, if the input voltage is higher than the pre-set alarm level, the controller reports an AC input
over-voltage alarm. The DC output voltage is also sampled and sent to the controller. If the output
voltage is lower than the pre-set alarm level, the controller will report a DC Low alarm. Likewise, if the DC
output voltage is higher than the pre-set alarm, the controller reports a DC output High alarm. The power
supply module status is communicated to the controller via an internal RS485 bus. If the power supply
modules issues an alarm, the alarm is passed to the controller. Power supply module failure alarms
include: AC input failure, DC output failure, fan failure, high output voltage, current limit, over
temperature, and module shut-down.
Communicate with deamon systems — The controller supports interface to the Switch 7750 chassis
through RS232 or RS485 cable connection. A cable is provided with the PoE Power Rack for attachment
to the Switch 7750 (connect the RS232 connector end to the PoE Power Rack and connect the RJ45
cable end to the port labeled "Com" next to the PoE DC terminal block on the back of the Switch 7750).
Using CLI commands, the User can receive and read system information or command the operation of
the PoE Power Rack.
There is one RS485 port and one RS232 interface on the rear panel of the PoE Power Rack (the cable
provided with the PoE Power Rack is a RS232 cable type).
The RS485 and RS232 signals are as follows:
Table 2-2 RS485:
Table2-3 RS232:
Pin
1
2
3
4
5
6
7
8
Pin
1
2
3
4
5
6
Definition
Receive, +
Receive, -
Transmit, +
Ground
Not used
Transmit, -
Ground
Not used
Definition
Not used
Receive
Transmit
Not used
Ground
Not used
2-3
Chapter 2 System Description