Electro Magnetic Compatibility (Emc) Features; Midplane Keying; Cooling System; Fan Tray Unit - Nortel Media Gateway 3500 Installation, Operation And Maintenance Manual

2.3.2.2

Electro Magnetic Compatibility (EMC) Features

The chassis is designed to comply with known EMC/RFI standards, including FCC Part 15,
Class A; ICES-003, Class A; EN 55022, Class A; EN 300 386.
Compliance measures include:
Venting holes - for air intake and exhaust, sized to provide for blockage of frequencies
within the specified range
Blank panels with contact fingers - used for covering empty slots when a configuration
requires such
RFI filters - built-in to the DC power inputs, assuring that conductive interference does
not reach the Power Supply Modules, or that switching signals generated by the Power
Supply Modules do not propagate over the main feed
Air filters - integrates a honeycomb EMI shield in its assembly. The honeycomb
structure consists of "cells" that are engineered to trap and absorb EMI noise while
maintaining 95% to 99% aperture for minimal airflow impedance. A gasket installed
around the frame makes sure there is conductivity of the frame to the enclosure.
2.3.2.3

Midplane Keying

Each slot is equipped with a key on the midplane to match the appropriate board type in
order to prevent inserting a wrong board type into the slot.
Note:
2.4

Cooling System

2.4.1 Cooling System
The Media Gateway 3500 components are cooled by a Fan Tray unit, located at the left of
the card cage. The Fan Tray Unit draws air in through a perforated grill at the right side of
the chassis.
The incoming air passes through a removable filter (located within the fan assembly,
immediately inside the perforated grill), whose honeycombed design prevents RF
interference.
The clean air is drawn by the fans and passes through the entire set of plug-in front and
rear boards residing in the slots, cooling each one. The air exits the Media Gateway 3500
via perforated vents of the chassis.
Blank panels are used to cover all unoccupied slots (as per the customer's configuration)
on both sides of the chassis. The front blank panels are especially constructed to allow
optimal air flow within the chassis.
2.4.2

Fan Tray Unit

Installation, Operation, Maintenance Manual
While the slot keys on the midplane are designed to prevent the insertion of
a board in an incorrect location, be sure NOT to force a board into a slot to
avoid damaging either the board or the midplane.
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Media Gateway 3500
Document # LTRT-90704