Cat6-cabling and catalysts

[kvanhoyw]

Hi,

we're having a bit of an argument with our cabling-company about the many ESD-problems we have (blown ports, connectivity-issues mostly solved by "idledetect", etc...).

They have now requested from us that we show some kind of proof that the catalysts support cat5e or cat6-cables. We mostly use c2924, c2950, c2948g and c2980g(a).

I found some info about this at http://www.cisco.com/en/US/partner/products/hw/switches/ps700/products_tech_note09186a00800a7af7.shtml. This page suggests that cat6 can be used on c2950-switches. But it also seems to tell this is not the case for the older c2924-range. And there is no info at all on c2948/c2980. I know these last are usually refered to as "series 4000", but the page explicitly mentions only c4003/c4006.

So, can we safely use cat5e/6 cables on c2924, c2948 and c2980? Anybody know of any other cisco info-pages on this issue?

Thanks.

[glen.grant]

I can't imagine it would be a problem using these cables that are more immune to noise and external factors . These should be better and work with an existing equipment . The C2948 ,C2980 use the same Cat 4000 code and are from the same era they should work without a problem . the 2924 I don't know , don't know why it wouldn't though .

[p.greuniesen]

Hello,

We use Cat 5 and Cat 5e on WS-C2950-24 and WS-C2950C-24 switches. It is not the performance ratings of these cables that cause the ESD. It could be many things such as not wearing a grounded wrist strap when performing maintenance on the switches. For example, today we have approximately 27% relative humidity in the building - it is very dry today. Every time we walk any distance across a carpet and touch the switch, we transfer the static energy built up in our bodies directly to the switch when we happen to touch a metal switch port. It's low current, but it is approximately 30Kv or more.You can easily feel this static zap. If you are wearing a grounded wrist strap with protective resister in like most straps have, the static buildup in the body is continuously bled off and you will not zap the switch port. If ESD is really your problem with the port failures, some things you can do to prevent this problem is to keep the proper humidity levels such as around 40% or so. Make sure you are using the shielded, grounded power cord that comes with the switch and that your building carries the ground properly all the way back to the grid, and if possible bolt the switches into a grounded relay rack which provides a convenient place to attach your static-preventing wrist strap before connecting and removing cables from the switch. It might not necessary be ESD that's taking out ports, it could be power surges coming in through the AC power distribution. You could help dampen these by placing every switch on a UPS. If you are using Screened twisted pair cable, which Cisco often recommends in office environments, as well as what we require for industrial invironments and the switches, this shieled version of the Cat5 and Cat5e cable provides additional protecting against EMI/RFI noise caused by other equipment. If you are using screened twisted pair cable (ScTP), depending on the installation, you would only want the shielded connector to be on the swtich port and an isolated connector on the PC port to prevent ground loops. THis is expecially important on long cable runs because you want to avoid ground currents on the shield which could also take out ports if they are high enough. You might want to hire a power/ground expert to certify your installation. We do this all the time for the systems we manufacturing and sell.

Hope this helps you.

Paul Greuniesen

Emerson Process Management

Austin