Dell PowerEdge R900 - Manual (Page 20)

20 About Your System
Connecting External Devices
When connecting external devices to your system, follow these guidelines:
• Most devices must be connected to a specific connector and device drivers
must be installed before the device operates properly. (Device drivers are
normally included with your operating system software or with the device
itself.) See the documentation that accompanied the device for specific
installation and configuration instructions.
• Always attach external devices while your system and the device are turned
off. Next, turn on any external devices before turning on the system
(unless the documentation for the device specifies otherwise).
For information about individual connectors, see "Jumpers and Connectors"
on page 153. For information about enabling, disabling, and configuring I/O
ports and connectors, see "Using the System Setup Program" on page 41.
Power Indicator Codes
The power button on the front panel controls the power input to the system's
power supplies. The power indicator lights green when the system is on.
The indicators on the redundant power supplies show whether power is
present or whether a power fault has occurred (see Figure 1-4). Table 1-3 lists
the power supply indicator codes.