Electromagnetic Environment Requirements - 3Com Router 3030 Installation Manual

22 C 3: I
HAPTER NSTALLING THE
ESD Preventative
Requirements
Electromagnetic
Environment
Requirements
R
OUTER
The routers also have rigorous demands on the content of salts, acids and sulfides
in the air. These harmful gases will speed up the aging processes of certain parts
and cause a more rapid rusting of the metal parts. The equipment room should be
protected from the invasion of harmful gases such as SO2, H2S, NO2, NH3, and
Cl2, the value limits of which are shown below:
Table 3 Value limits for harmful gas content in equipment room
Gas Average (mg/m
SO 0.2
2
H S 0
2
NO 0.04
2
NH 0.05
3
Cl 0.01
2
Although many anti-static considerations have been given to 3000 DSL Family,
damage to the router's circuit or even the whole equipment is still posible when
the static electricity exceeds the tolerance threshold.
In the communication network to which the routers are connected, static
induction mainly comes from:
External electric fields such as outdoor high voltage power lines or thunder.
Internal environment like flooring materials or the whole equipment
structure.
The following should be considered to safeguard the equipment against the ESD:
Make sure that the equipment and the floor are well grounded.
Make sure that dust-proof measures are taken.
Maintain an appropriate humidity and temperature.
Wear an ESD-preventive wrist strap and uniform when contacting the circuit
board.
Place the uninstalled circuit board on the antistatic workbench, with its face
upward, or put it into the static shielding bag.
When observing or removing the uninstalled circuit board, please touch the
edge of the circuit board, and avoid contacting the devices on it.
The interference sources, no matter where they come from, affect the routers with
capacitance coupling, inductance coupling, radiation of electromagnetic wave,
common impedance (including the grounding system) or conducting line (power
line, signal line and transmission line etc.). The following should be considered:
Take effective measures to prevent the power system from being interfered
with by the power grid system.
Keep the router far away from the radio launcher, radar launcher, and
high-frequency devices working in high currents.
Use electromagnetic shielding when necessary.
3 3
) Max. (mg/m )
1.5
0.03
0.15
0.15
0.3