3Com 4800G Getting Started Guide - Page 26

26 CHAPTER 2: PREPARATING TO INSTALL THE SWITCH For the temperature and humidity requirements of different models, refer to section "System Specifications of the Switch 4800G Series" on page 22. Cleanness Dust is a hazard to the operating safety of your device. The dust accumulated on the chassis can be adsorbed by static electricity and result in poor contact of metal connectors or metal contact points. Especially when the indoor relative humidity is low, electrostatic adsorption is more likely to happen. This can not only shorten the service life of your device but also cause communications failures. The following table lists the dust concentration limit. Table 10 Dust concentration limit in the equipment room Substance Concentration limit (particles//m3) Dust ≤ 3 x 104 (no visible dust on the tabletop over three days) Note: The dust diameter is greater than or equal to 5 μm. Besides dust, there are rigorous limits on the content of harmful substances in the air that can accelerate the corrosion and aging of metals, such as chloride, acid, and sulfide in the equipment room. The equipment room must be protected against ingression of harmful gases such as SO2, H2S, NH3, and Cl2. For specific requirements, see Table 11. Table 11 Harmful gas limits in the equipment room Gas Maximum concentration (mg/m3) SO2 0.2 H2S 0.006 NH3 0.05 Cl2 0.01 Electromagnetic Susceptibility The operation of your switch can be affected by external interferences, such as conducted emission by capacitance coupling, inductance coupling, electromagnetic wave radiation, and common impedance (including the grounding system) coupling, and leads (power cables, signaling cables and output wires). To eliminate the interferences, pay attention to the following: ■ As the AC power system is a TN system, use a single-phase three-wire power socket with a protection earth (PE) to effectively filter interference from the power grid. ■ Keep the device far away from radio transmitting stations, radar stations, and high-frequency devices. ■ Use electromagnetic shielding, for example, shielded interface cables, when necessary. ■ Route interface cables only indoors to prevent signal ports from getting damaged by over-voltage or over-current caused by lightning strikes. Laser Safety The Switch 4800G are Class 1 laser devices. c CAUTION: When an optional interface module or SFP module on the Switch 4800G is operating, do not stare into the optical port because the laser light emitted from the optical fiber may hurt your eyes.