Hardware Component Overview
YELLOW ALARM (see Figure 16). A system condition that causes the red or yellow
alarm LED to light on the craft interface also activates the corresponding alarm
relay contact. For instructions forattaching a device to the alarm relay contacts,
see “Connecting to an External Alarm-ReportingDevice” on page 115.
Figure 16: Alarm Relay Contacts and BITS InputPor ts
BITS A
BITS B
LINK
RED ALARM
YELLOW
ALARM
LINK
1173
Alarm relay
contacts
BITS
input ports
NC
C
NO
NC
C
NO
Power System
The router uses DC power. There are two load-sharing, pass-throughpower supplies
located at the bottom rear of the chassis, as shown in Figure 2. The power supplie s
connect to the midplane,which distributes power to router components according
to their individual voltage requirements. When the power supplies are installed
and operational, they automaticallyshare the electrical load. If a powersupply
stops functioning for any reason, the remaining p owers upplies instantly begin
providing all the power the router needs for normal functioning and can provide
full power indefinitely.
Power supplies are hot-removable and hot-insertable, as described in
Field-ReplaceableUnits (FRUs) on page 4. Toavoid electrical injury, carefullyfollow
the instructions in “Replacinga Power Supply” on page 197.
NOTE: After poweringoff a power supply, wait at least60 seconds before turning
it back on. After powering on a power supply, wait at least 60 seconds before
turning it off.
If the router is completely powered down when you power on the power supply,
the Routing Engine boots as the powersupply completes its startup sequence. If
Power System 35