Specifications

2-10 Cisco MGX 8220 Reference, Release 4.1
Cooling Assemblies
Main Cooling Assembly
The main cooling assembly measures:
• 5.25 inches (3u) high
• 17.45 inches wide
• 22 inches deep
The main cooling assembly is capable of providing cooling for up to two MGX 8220 shelves and is
mounted in the rack below the shelf (or shelves). The cooling assembly consists of fans which draw
air through the front and exhaust air upwards through the shelf. An illustration of the cooling
assembly is shown in Figure2-9.
Figure2-9 Cooling Assembly
Booster Cooling Assembly
The booster cooling assembly measures:
• 3.5 inches (2u) high
• 17.45 inches wide
• 22 inches deep
The booster cooling assembly is used in racks with more than two MGX 8220 shelves and is
mounted above the shelves cooled by the main cooling assembly and below the shelves to which the
booster cooling is to be provided. The booster cooling assembly consists of fans which draw air from
the shelves below and exhaust air upwards through the shelf or shelves above. Each booster supports
an additional two MGX 8220 shelves. A system of up to six MGX 8220 shelves can be supported
(using one main cooling unit and two booster cooling units).
Cooling Assembly Power
For both cooling assemblies, power is supplied to the connector at the rear of the cooling assembly
by a cable running from the connector in the middle bottom rear of the MGX 8220 shelf.
The assemblies provide output signals to the shelf. Using these signals, the performance of the
cooling assemblies can be monitored by the BNM cards. The cable delivering DC power to the
cooling assembly from the MGX 8220 shelf also carries these signals to the BNM via the backplane.
The signals are such that the model of cooling assembly can be identified and the speed of each fan
can be monitored (each fan generates a fixed number of square-wave pulses per revolution allowing
the speed of the fan to be determined).