Site Selection Guidelines; Rack Requirements - Cisco 900 Series Hardware Installation Manual

Prepare for Router Installation
Warning
To prevent the system from overheating, do not operate the devices in an area that exceeds the maximum
recommended ambient temperature. Statement 1047.
Table 3: Ambient Temperature of SKUs
Internal PSU
External PSU
Note
For altitudes above sea-level, de-rate the ambient operating temperature 1°C per 1000-feet of elevation.
Note Cisco 900 series routers are fanless, normally run warm to the touch, and require adequate clearances for
proper heat dissipation and ventilation.

Site Selection Guidelines

The Cisco 900 Series ISRs require specific environmental operating conditions. Temperature, humidity,
altitude, and vibration can affect the performance and reliability of the router. The following sections provide
specific information to help you plan for the proper operating environment.
The Cisco 900 Series ISRs are designed to meet the industry EMC, safety, and environmental standards
described in the Regulatory Compliance and Safety Information for the Cisco 900 Series ISR document.

Rack Requirements

Routers with internal Power Supplies can be mounted in a 19-inch rack using rack-mount brackets (optional
kit). Routers with external Power Supplies require a customer-provided tray for mounting in a rack.
The following information helps you plan your equipment rack configuration:
• Allow clearance around the rack for maintenance.
• Allow at least one rack unit of vertical space between routers; more clearance is required when stacking
SKU
multiple Cisco 900 Series ISRs. Provide adequate heat removal mechanism so that heat does not build
up in the rack and the air surrounding the router is well within the specified operating ambient temperature
condition.
Hardware Installation Guide for the Cisco 900 Series Integrated Services Router
C921-4P
C931-4P
C921J-4P
C926-4P
C927-4P
C927-4PM
Site Selection Guidelines
Ambient Temperature
50 °C
45 °C
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