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Catalyst test cable-diagnostics tdr - short/crosstalk

Level 1
Level 1

So I had one user complain about connection issues to our mailserver and for phone calls. I did run a test cable-diagnostics tdr on his switchport and it came back with pairs C & D as short/crosstalk. Swaped the cables but still the same.

I also checked some other ports and from like 10 ports I checked about half of them had short/crosstalk on pairs C & D. All ports are 1 gig copper ports.

The users do not report any issues so I wonder if this is like normal for some cable types?

5 Replies 5

Leo Laohoo
Hall of Fame
Hall of Fame
That's not correct. 1 Gbps ports should be "Normal". "short/crosstalk" means there is something wrong with the cable.
What firmware is the switch running on?

Ah, yes, the firmware hasn't been updated in a while...

We're on 12.2(55)SE3.

Hmmmm ... What is the uptime of this switch? Is it >12 months?

No, it's about two month as we had some work done on the electricity circuits at that time.

Martin L


I have seen this before; Told my tech to check cables at connectors and pull new cable.  2 possibility:

I think he screwed up cable termination and since the device worked ok, (not PoE device), tech was not eager to work on this.  so, not sure If he fixed in the end or not. 

What do you mean by "Swaped the cable" ?  and where ? I asked my tech to pull new cable and use Cat6. Again, not sure if he did and if that fixed problem since device was OK.



Regards, ML
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