Juniper EX9214

zone. Four power supplies provide full redundancy. If a power supply in a redundant conguraon is
removed or fails, its redundant power supply takes over without interrupon. The power supply in
PEM2 serves as redundant power supply to the power supply in slot PEM0 and the power supply in
PEM3 serves as redundant power supply to the power supply in slot PEM1. See "DC Power Supply in
an EX9214 Switch" on page 52.
• Cooling system—The cooling system in an EX9214 switch consists of two fan trays and one air lter.
Each fan tray contains six fans. Under normal operang condions, the fans in the fan trays run at
less than full speed. If one of the fans fails, the host subsystem increases the speed of the remaining
fans to provide sucient cooling for the switch indenitely. See "EX9214 Cooling System" on page
40.
Cra Interface in an EX9200 Switch
IN THIS SECTION
Host Subsystem LEDs | 31
Fan LEDs | 32
Power Supply (PEM) LEDs | 33
Switch Fabric LEDs and Control Buons | 33
Line Card LEDs and Control Buons | 34
Alarm LEDs and Alarm Cuto Buon | 34
Alarm Relay Contacts | 35
The cra interface enables you to view status and troubleshoong informaon at a glance and to
perform many system control funcons. The cra interface is located on the front panel of the switch. It
contains LEDs and on and o buons for switch components, the alarm relay contacts, and an alarm
cuto buon.
29