3Com 8814 Switch User Manual


 
48 CHAPTER 3: INSTALLATION PREPARATION
Wearing an
ESD-Preventive Wrist
Strap
To prevent the electronic components from being damaged by the electrostatic
discharge (ESD), take ESD measures for the area where the switch is located and
note the issues below:
Always wear an ESD-preventive wrist strap when installing the parts, especially
the electric printed circuit boards.
Hold the circuit board by the edge. Do not touch the components or the
electric printed circuit.
Take the following steps to use the ESD-preventive wrist strap.
Step 1: Wear the wrist strap on your wrist.
Step 2: Lock the wrist strap tight around your wrist to keep good contact with the
skin.
Step 3: Insert it into the hole peculiar to ESD-preventive wrist strap in the chassis
or attach it to the grounding screw of the chassis the alligator clips.
Step 4: Make sure that the ESD-preventive wrist strap is well grounded.
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CAUTION: For the sake of safety, check the resistance of the ESD-preventive wrist
strap. The resistance reading should be in the range of 1 to 10 Mohm between
human body and the ground.
Safety
Recommendations
against Laser
Some I/O modules of the Switch 8800 Family have optical interfaces. In operating
status, it is dangerous to stare into the open optical interface because the laser
being transmitted through the optical fiber produces a small beam of light which
has very high power density and is invisible to human eyes; when a beam of light
enters the eye, retina may be burned.
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CAUTION: The laser inside the optical fiber may hurt your eyes.
Examining Installation
Site
The Switch 8800 Family can only be used indoors. To ensure that the switch works
normally and to prolong its service lifetime, the following requirements should be
met in terms of installation environment.
Temperature/Humidity
Requirements
To ensure the normal operation and service lifetime of a switch, proper
temperature and humidity should be maintained in the equipment room.
Long-lasting high humidity in the equipment room is prone to poor insulation or
even leakage of the insulating material. Sometimes, the mechanical performance
deterioration, the rustiness and corrosion of some metal parts are also more likely
to occur. If the relative humidity is too low, the captive screws may become loose
due to the insulation washer contraction. Meanwhile, the electrostatic is likely to
be produced in the dry environment, which will jeopardize the CMOS circuit of the
switch. The higher the temperature, the greater the damage it will do to the
switch. Long-lasting high temperature will speed up the aging process of the
insulating materials, greatly lower the reliability of the switch, and therefore affect
its service life seriously.