cross connect reliability

Mon Sep 21 06:48:56 UTC 2009

Luke S Crawford wrote:
> Richard A Steenbergen <ras at e-gerbil.net> writes:
>> You've never seen a single port go bad on a switch? I can't even count
>> the number of times I've seen that happen. Not that I'm not suggesting 
>> the OP wasn't the victim of a human error like unplugging the wrong port 
>> and they just lied to him, that happens even more.
> 
> I know it happens;  it's happened to me, and I have probably touched fewer
> switches than you.  Still, from what I can understand, it can be
> prevented/minimized by the use of a grounded port.
> 
> 
> from: 
> http://support.3com.com/documents/switches/baseline/3Com-Switch-Family_Safety-Reg-Info.pdf
> 
> 
> "CAUTION: If you want to install the Switch using a Category 5E or
> Category 6 cable, 3Com recommends that you briefly connect the cable
> to a grounded port before you connect to the network equipment. If you
> do not, the cable’s electrostatic discharge (ESD) may damage the Switch's
> port.
> 
> You can create a grounded port by connecting all wires at one end of a
> UTP cable to an earth ground point, and the other end to a female RJ-45
> connector located, for example, on a Switch rack or patch panel. The
> RJ-45 connector is now a grounded port."
> 

HP chassis switches ship with a grounding jack accessory you attach to
the DB9 port (I assume it ties all RJ-45 pins to shied/ground)
explicitly for this purpose. The instructions say to always plug a cable
into the grounding device before connecting to a switch port.

~Seth