Cabling and connections
Category cable and RJ-45 connectors are certainly not unique to A/V installations, but have been typically used for network communication and audio/video transport. But why not loudspeaker connections?

The ANSI TIA/EIA 568 standard indicates that the individual conductors in a CAT cable are required to be between 22 AWG and 26 AWG. AWG wire gauges are based on the cross sectional area of the wire. When multiple wires are used in parallel the resulting AWG is based off the total cross sectional area of all wires summed together.

Standard CAT cable has 4 pairs of conductors (8 wires). The table below shows the equivalent gauge with 4 of these conductors in parallel. By using 2 sets of 4 conductors in parallel, 22 AWG CAT cable is equivalent to common 16/2 speaker cable. Even 26 AWG CAT cable is still equivalent to 20/2 speaker cable..

Both the C-IC6 and AMP-450BP utilize pins 1,2,3, and 6 for speaker (+) and pins 4,5,7, and 8 for speaker (-).

This equates to pairs 1 and 4 (Blue/Brown) for speaker (-) and pairs 2 and 3 (Orange/Green) for speaker (+). Due to this assignment, the resultant connection will be correct regardless of whether T568-A or T-568-B is used. Even a crossover cable will end up with the same pairs utilized for speaker (+) and speaker (-).

The maximum recommended distance from the AMP-450BP to the C-IC6 is 40 meters, or about 130 feet. At this distance there will be almost 3dB loss at the speaker. However, this is specified with the worst case scenario of using 26AWG CAT cable.

Standard CAT-5e cable generally uses 24 AWG conductors, which will allow for runs up to 23 meters (75 feet) before a loss of 1dB is incurred.

Please note that there is no designation or recommendation made regarding the type of CAT cable to use outside of wire gauge. Shielded cable is NOT required. CAT5e or CAT6a will work just fine, but so will any other standards based category cable terminated with RJ-45 connectors.

The RJ-45 and euroblock connectors are all wired in parallel. Either one or a mix of each could be used depending on the requirements of the installation.

In most cases, when it comes to cabling and connectivity, it’s better to play it safe instead of cutting it close. For example: You don’t want a cabling system that can barely support your current application requirements. A system that is fully capable of handling current application bandwidth needs, as well as future needs, offers more peace of mind, ensures continued productivity and reduces the need for costly upgrades later.

The same holds true when talking about cable insertion loss margin. Insertion loss is the ratio of received to inserted signal power at the end of a cable and is dominated by the cable attenuation. Expressed in decibels (dB), insertion loss levels increase as cable temperature rises.

Cable insertion loss margin represents the difference between the cable’s measured insertion loss and the maximum insertion loss level allowed per standards; the higher the margin, the better the cable performance. Cutting it close when it comes to cable insertion loss margin doesn’t leave much wiggle room for cable temperature levels to rise without experiencing negative impacts.

What the Requirements Say

The insertion loss requirement given in the standards is at 20 degrees C. If cable temperatures exceed that level, which reduces insertion loss margin, performance requirements must change to accommodate the higher temperatures – otherwise, you’re not taking full advantage of what your cabling system has to offer.

If controlling the temperature of the environment is not an option, channel lengths must be shortened to continue to move data along the cable; otherwise, data transmission will suffer (there will be too much cable loss for successful transmission). How much the channel needs to be shortened depends on the construction and type of category cable being used: Category 5e, 6 or 6A. Reduced cable insertion loss margin will also reduce information capacity, lowering signal-to-noise ratios (which indicate the relationship between desired signals and background noise levels).

Sufficient Insertion Loss Margin

Sufficient cable insertion loss margin is especially crucial in Power over Ethernet (PoE) applications, as well as in digital buildings and IoT environments, where DC current is running through cable bundles along with the data, causing heat build-up if it doesn’t have a chance to dissipate into the environment.

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Basically the quote you have shown was written by someone who either didn’t understand what they were talking about, or oversimplified it.

The bandwidth of the cable is a result of the resistance of the cable and the fact that it is capacitive. These act like an R-C low pass filter limiting the bandwidth. Additionally the distributed inductance and capacitance of the cable are frequency dependent so have a more complex affect on the bandwidth.

The “insertion loss” which is a measure of the gain of the cable is dependant on both frequency, but also on length. The longer the cable, the more lossy it is.

Here is one example of the insertion loss of a CAT5e cable, this for a 100m length

Here we see that at 100MHz, the loss is actually more than 20dB – a lot more than the 3dB (power gain) or 6dB (voltage gain) point that would be used to specify the bandwidth of a first order low-pass filter as the quote implies.

Further up the Wikipedia page more accurately explains where the 100MHz figure comes from:

The specification for category 5 cable was defined in ANSI/TIA/EIA-568-A, with clarification in TSB-95. These documents specify performance characteristics and test requirements for frequencies up to 100 MHz

Basically, the requirements in terms of insertion loss that must be met for a cable to be classified as Cat5 are only specified up to 100MHz. Beyond this point the specifications of the cable are undefined by the standard – though manufacturers may well provide data at the higher frequencies.

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The difference between Cat5 and Cat5e is in the way the cables pairs are twisted. The twist in a Cat5e is tighter and this is done to reduce crosstalk.

Fast ethernet (100Mbps) uses only 2 pairs (one for TX and one for RX). Gigabit ethernet uses all 4 pairs for RX and TX at the time (using echo cancellation) which makes it very sensitive to crosstalk.

Propagation delay varied from 450 to 500 nsec over different cable samples (be careful using propagation delay to measure length!)

Delay skew less than 15 nsecover various cable samples

Lots of Cat 5e cable performs muchbetter than specified TIA/ISO limits•Most significant channel degradations are due to connectors•Poor connectors can significantly increase internalcrosstalkand reduce return loss•TIA/ISO limits are designed for worst-case pass/fail limit bounds–Never intended as a typical channel characterization–Provide margin for test equipment imperfections and measurement noise–Use of extrapolated TIA/ISO insertion loss limits as a channel model is very pessimistic with respect to a typical Cat 5e channel•Typical Cat 5e channel insertion loss at room temperature can beapproximated by the extrapolated Cat 6 channel limit line
Significant channel degradations can be mitigated by replacing connectors

Most people think that the reach of Ethernet is 100 meters — at true statement for a system operating at 20°C. We usually do not discuss what limits the reach of the cable. For the discussion at hand today, I will assume that signal attenuation limits the reach of the cable. There are other factors that can limit the reach of a system, but for today we will only look at signal attenuation.

CAT5e insertion loss (90 meter in wall and 10 meter patch cable)
10 MHz 7.1 dB
20 MHz 10.2 dB
100 MHz 24 dB

Cat 5e stranded cable table shall meet the values computed by multiplying the horizontal cable insertion loss requirement in clause 4.3.4.7 by a factor of 1.2 (the de-rating factor), for all frequencies from 1 MHz to 100 MHz. The de-rating factor is to allow a 20% increase in insertion loss for stranded construction and design differences.

https://www.connectixcablingsystems.com/themes/ccs_2019/pdf/Cat5e,%20Cat6%20and%20Cat6a%20difference.pdf
CAT 6
100 MHz 18.6 dB
250 MHz 31.1 dB

CAT 6A
100 MHz 18.6 dB
250 MHz 29.5 dB
500 MHz 43.8 dB