3com S7906E Guide D’Installation Rapide

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Gas 
Maximum concentration (mg/m3) 
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2
 
0.01 
 
Anti-static Requirements 
Any possible interference sources, no matter outside or inside the system, affect the switch in use may 
in a way of capacitance coupling, inductance coupling, radiation of electromagnetic wave, common 
impedance (including the grounding system) coupling or conducting line (power line, signaling line and 
transmission line etc.).Therefore, the following should be considered: 
z
 
Adopt effective measures to protect the power supply system against the power grid interference. 
z
 
Separate the working ground of the switch from the ground device of the power supply equipment 
or lightning-protection ground device as far as possible. 
z
 
Keep the switch far away from the radio launcher, radar launcher, and high-frequency devices 
working in high currents. 
If necessary, adopt electromagnetic shield. 
Grounding Requirements 
A good grounding system is the basis for a switch to work stably and reliably and the important 
guarantee of lightning protection, anti-interference and ESD. A user should provide good grounding 
system for the switch and the grounding resistance should be less than 1.5 ohm. 
Power Supply Requirements 
For the power supply requirements, refer to section 1.2.3 “Power Supply System” in Chapter 1 “Product 
Overview”. 
Installation Planning 
Since the S7900E series are a kind of complex equipment, it is necessary to make a good plan and 
arrangement concerning installation position, networking mode, power supply and cabling before 
installation. 
Installation Space Requirement 
For better heat dissipation and equipment maintenance, it is recommended that the front and back of 
the switch should be at least one meter away from walls or other devices, and that the left and right of 
the switch should be at least 0.8 meters away from walls. If a rack is to be installed, the headroom 
should be 3 meters at least. 
If the above-mentioned requirements are not satisfied, it will be very inconvenient to install a rack or 
install air filters on the switch. 
Rack-Mounting Requirements 
Before rack-mounting a switch, make sure the rack meets the following requirements: 
z
 
Better mount a switch in an open rack. However, if you mount a switch in a closed rack, make sure 
of good heat dissipation system. 
z
 
Make sure the rack stands steadily enough to well support the switch and accessories.