Power-On/Off Control - Cisco Internet Router 12404 Technical Specifications

Appendix A Technical Specifications

Power-On/Off Control

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directly from the power supply and performs the functions of power-up/down
control, device discovery, code download, diagnostics, and environmental
monitoring and alarms.
Based on commands it receives from its on-board EPROM and from the master
RP, each MBus module directly controls the DC-DC converters on the component
to which it is mounted. Each MBus module is tied directly to +5 VDC from the
power supply. When power is applied to the Cisco 12404 Internet router, all
MBus modules immediately power on. The MBus modules on the RP or CSF
immediately turn on the DC-DC converter, powering up the respective card. The
line card MBus module waits to power on the line card until it receives a command
from the master RP.
Device discovery—The RP can determine the system configuration using the
•
MBus. A message is sent from the RP over the MBus requesting all installed
devices to identify themselves. The response back provides slot number, card
and component type.
• Code download—A portion of the line card operating software can be
downloaded from the RP to the line card over the MBus. Because the MBus
is relatively slow compared to the CSF, only enough code is downloaded to
the line card for it to access the CSF and complete the download process.
• Diagnostics—The diagnostic software image is downloaded from the RP to
the card under test.
• Environmental Monitoring and Alarms—The MBus module on each
component monitors that component's environment as follows:
Line cards and the RP are monitored for temperature by two temperature
–
sensors mounted on each card. The MBus module makes voltage
adjustments through software for the +2.5, +3.3, and +5 VDC DC-DC
converters.
The CSF is monitored for temperature by two temperature sensors
–
mounted on each card. The MBus module makes voltage adjustments
through software for the +2.5, +3.3, and +5 VDC DC-DC converters.
Environmental monitoring includes voltage monitoring, temperature
–
monitoring, fan tray assembly and rotational sensing for each fan in the
fan tray.
Cisco 12404 Internet Router Installation and Configuration Guide
Maintenance Bus
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