Talk:Category 5 cable

Cat 5 v Cat 5e

Can we get more info on the differences between Cat 5 & 5e? I seem to remember that before Cat 6 was finalised we used Cat 5e cable for 1000Mb/s?

--Quatermass (talk) 22:57, 11 December 2011 (UTC)

Cat 5 Manufacturing

Many Cisco students are required to make a Cat 5 cable but often ask how such a complex process can be automated. Can a link be included to a manufacturers website or a video on YouTube showing how this process is automated?

Robinatilio (talk) 12:02, 12 July 2008 (UTC)

That's an excellent request, and something i've wondered. I don't have a video, but i share your desire to see one. Cheers! —fudoreaper (talk) 00:06, 22 October 2009 (UTC)

I always assumed that they just used cheap third world labour to make them. Plugwash (talk) 01:37, 16 January 2010 (UTC)

Have a look here (old machines but not 3rd world I assume) --Copa017 (talk) 08:12, 1 April 2011 (UTC)

That shows how cable is made (though dispite the title the cable they are making doesn't look like cat5 to me) but the original posters question seemed to be how cat5 patch cable assemblies are made commercially. I just don't see any reasonable way to automate the process of seperating out the cores and arranging them by color code. Plugwash (talk) 11:05, 8 September 2011 (UTC)

Tautologies in lede

I'm amazed that a particular editor is still having this problem but since theat is the case maybe I need to be more explicit:

• Ethernet is a digital signal (even Gigabit)
• ATM is also a digital signal

Analog and digital are a) not capitialised and b) not signals, but broad classes of signal. In fact, if we neglect hybrid, they are the only classes of signal. Therefore we can't use them as examples of signals because they are not specific. Reducing the proposed amendments down we end up with something like "This type of cable is used in structured cabling for computer networks such as one signal and another signal, also used to carry many other signals such any class of signal."

This is undoubtedly true (neglecting the intrinsic limitations of the cable) but an obvious tautology. We don't need to confuse the reader with this, who is going to wonder what he has missed. And yes, Sgeeves, I do know what I am talking about: it is not me that is repeatedly adding a frankly idiotic statement and insisting it is some significant revelation. Crispmuncher (talk) 15:41, 12 May 2011 (UTC).

Bandwidth

The article currently claims Cat 5e UTP has a cutoff frequency of "50323 Hz" (which seems excessively precise). A cutoff frequency of about 51 kHz seems insufficient to support the 125 Mbaud used in 100BASE-TX#100BASE-TX and also in Gigabit_Ethernet#1000BASE-T. If there is some some bandwidth (signal processing) trick to getting symbol rate over 3 orders of magnitude faster than the cutoff frequency, could we mention it in this article or at least link to some other article where that trick is described? --DavidCary (talk) 17:56, 3 September 2011 (UTC)

Examining the reference, it appears that this was calculated from resistance and inductance. In addition to excessive precision, it looks like there was an error in the calculation. I have corrected it. Below the corner frequency, the cable does not have constant characteristic impedance and thus is no longer a well-behaved transmission line. Other math comes in to play when operating at these lower frequencies. All of this either deserves elaboration in the article (and I don't feel like I can do it without original research) or some of these details should be removed. --Kvng (talk) 14:08, 5 September 2011 (UTC)

Shielding

I've just re-undone an edit made by Kvng regarding the properties of the screen. The section he cites is not relevant since the screen does not form a Faraday cage. By definition a Faraday cage is isolated to ensure an induced charge may form to counteract the applied field. In contrast, the shield here is firmly grounded (IEEE 802.3 27.5.2.2) to ensure no charge may form on the screen. By enclosing the central conductors in a screen held at ground potential it is ensured that there is no externally-applied electrical field within the body of the cable. This is why, for example, a 10BASE2 or 10BASE5 network wouldn't work reliably if the ground wire wasn't attached. It is also why STP connectors are needed - if the shield was left floating you wouldn't need to maintain its electrical continuity.

If you want further evidence of this simply take a look at the cables used by the professional audio guys - grounded shields are very much the order of the day, even though they are exclusively concerned with signals far below the 100kHz it is claimed shields are not effective at. Crispmuncher (talk) 06:30, 26 November 2011 (UTC).

The section I cite is Electromagnetic_shielding#Magnetic_shielding. The Faraday cage discussion is a red herring. There simply is no physical mechanism for a non-magnetic shield to stop these long-wavelength magnetic fields. Bill Whitlock's tutorial (http://www.aes.org/tutorials/) explains this in depth. Since that is a couple hours long and you need an AES membership to access, I'll offer an alternate reference that simply states the facts - Jim Brown (2004). "Chield Current Induced Noise part 2". SynAudCon. http://www.audiosystemsgroup.com/SCIN-2.pdf. Retrieved 2011-11-27. "Nearly all interference below a few hundred kHz is magnetically coupled. Cable shields provide almost no magnetic shielding in this range."  It is important to get this right. People need to know that using shielded cable does not give them permission to bundle signal wires with AC power. Professional audio guys use shielded cable to prevent radio frequencies from contaminating their signals. --Kvng (talk) 15:07, 27 November 2011 (UTC)