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I see patch panels all come rated as CAT5e, or CAT6 (and so on). I understand the difference between CAT5e and CAT6 cables, more stringent interference shielding, etc.

What I don't understand is why switches aren't rated as CAT5e or CAT6? Instead, they are just a Gigabit switch. They have a port, doesn't that make the port part of the connection? Shouldn't the port be rated CAT5e or CAT6 as well?

Edit:
Or to reverse the question: how are patch panel ports so different from switch ports that they require a rating?

Answer (for those that don't want to read through all the comments):
Because there is quite a bit of wiring between the patch panel jack's front contacts and the termination for the cable on the back, while the switch port's jacks only have 2mm of contact at the front.

Slav
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4 Answers4

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CATx are physical cable wiring standards, specifying physical wiring characteristics of the cable, like impedance, number of conductors, twist rate, etc.

Switches do not care about the physical properties of the cable. All they care about is whether or not the cable is able to successfully transmit data. It is assumed that cabling used will be within spec for whatever speed/duplex that is required, and depending on what speed uplink is required, there may be any number of physical cabling types that will work fine.

An analogy would be high voltage wiring, such as 12-3 romex. That describes the physical properties of the cable, not necessarily what it's going to be used for. 12-3 romex is rated to ~120v @ 15A or thereabouts. The wall sockets that 12-3 romex is terminated in are not called "12-3 romex sockets". They're called NEMA 5-15 sockets. It is assumed that the cabling terminated is up to spec.

EEAA
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    By that logic, shouldn't patch panels be also agnostic of the cable wiring standards? To be more clear: why are ports on patch panel CAT-rated, while ports on switches aren't? – Slav Aug 18 '15 at 18:07
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    No, that is not the case. Patch panels are very much part of the physical cable plant. The only part of the switch that is part of the physical plant is about 2mm of copper trace on the PCB. Again, if a switch port is advertised as supporting 1gb, it is assumed that it will support that PHY layer as long as the cabling is in spec. – EEAA Aug 18 '15 at 18:09
  • Not trying to argue, just trying to understand: isn't a patch panel port just 2mm of copper between a female and male connector too? Thank you for your time – Slav Aug 18 '15 at 19:57
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    No, patch panels are not double-ended female jacks. If you see those, run away, as they're horribly unreliable. Real patch panels include termination for copper wiring on the back and female RJ-45 jacks on the front, and the configuration of the termination posts are what determines if it's Cat5e, Cat6, etc. – EEAA Aug 18 '15 at 20:03
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    I think @Slav is asking: Switches have internal wiring, from the ports to whatever microchips, so why isn't that wiring CAT-rated? – user253751 Aug 19 '15 at 00:53
  • The jacks on switches are typically directly soldered to the PCB of the switch, there is no "internal wiring". – LawrenceC Aug 19 '15 at 01:36
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    @immibis They don't really have "wiring" unless you count a trace as "wiring." And it would be very hard for traces on a PCB (printed circuit board) to meet the CAT 5/6 standards, since those standards require that the conductors are shielded and _wrapped around each other with a certain number of twists per meter_. That would be one seriously difficult to fabricate PCB. As long as the 300 meter section of cable isn't leaking much, the 2 mm part on the PCB isn't going to be a problem. – reirab Aug 19 '15 at 04:44
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    @reirab Then the answer to the original question is "because they couldn't possibly meet the rating, and because the part of the wiring inside the switch is too short to matter". Not "switches don't care about the physical properties of the cable". – user253751 Aug 19 '15 at 05:24
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    @immibis Well, the real answer is basically, "Because switches are completely irrelevant to the CAT5/6 standards." And the reason for that is that switches and cables are completely separate concerns. The switch doesn't care about the cables and vice versa. Furthermore, the effective ways to prevent interference on a PCB are quite different from the ways for doing so in a 300 m section of wire in which 4 different high-frequency circuits are run in very close proximity, so using the same standard to specify their properties wouldn't make any sense. – reirab Aug 19 '15 at 06:32
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    I think my real confusion was not realizing that there is (a significant amount of) wiring **inside the patch panel jacks**. I considered the patch panel jacks to be the same "2mm trace" as the switch jacks. And the confusion was: "why are switch jacks exempt from rating, while patch panels jacks have to be rated". I now understand that patch panel jacks have additional wiring **between** their contact traces at front and termination points at the back (where the pairs are untwisted and punched). @immibis . Thank you all for clarifying – Slav Aug 19 '15 at 12:50
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The CAT system was created to describe the channel between two devices. In most cases, these two devices are a PC and a switch. So the switch is not part of the channel, and not part of the CAT system.

John Hanks
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"Cat 5" is part of the TIA/EIA-568 standards for "commercial building cabling for telecommunications products and services". Note that such cabling need not be used for Ethernet switching to be rated. Also, the organization in question has not chosen to rate switches.

The intent of these standards is to provide recommended practices for the design and installation of cabling systems that will support a wide variety of existing and future services.

(All emphasis is mine)

Catgories 3 and 5 and 6 cable are required for certain kinds of Ethernet, but the ratings were not originally intended to serve Ethernet networking specifically.

See: https://en.wikipedia.org/wiki/TIA/EIA-568

Todd Wilcox
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in my opinion the communication is done between two devices and each device need a certain signal level to detect digital format. When data speed is increased (i.e 100m to 1gb) then same cable will offer more resistance to drop signal levels that why different categories represent different manufacturing techniques to overcome signal losses.

Nasir Malik
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