Tests for Copper Cable Certification

Wiremap

The Wiremap test is used to identify physical errors of the installation; proper pin termination at each end, shorts between any two or more wires, continuity to the remote end, split pairs, crossed pairs, reversed pairs, and any other mis-wiring.

Propagation Delay

The Propagation Delay test tests for the time it takes for the signal to be sent from one end and received by the other end.

Delay Skew

The Delay Skew test tests for the difference in propagation delay between the fastest and slowest set of wire pairs. An ideal skew is between 25 and 50 nanoseconds over a 100 meter cable. The lower this skew the better, less than 25 ns is excellent, but 45 to 50 ns is marginal.

Cable Length

The Cable Length test verifies that the cable from the transmitter to receiver does not exceed the maximum recommended distance of 100 meters in a 10BASE-T/100BASE-TX/1000BASE-T network.

Insertion Loss

Insertion loss, also referred to as attenuation, refers to the loss of signal strength at the far end of a line compared to the signal that was introduced into the line. This loss is due to the electrical resistance of the copper cable, the loss of energy through the cable insulation and the impedance caused by the connectors. Insertion loss is usually expressed in decibels dB with a minus sign. Insertion loss increases with distance and frequency. For every 6dB of loss, the original signal will be half the original amplitude.

Decibels vs. Voltage

dB	Voltage Ratio	dB	Voltage Ratio		dB	Voltage Ratio	dB	Voltage Ratio
0	1V	-13	.224		-6	.500	-19	.112
-1	.891	-14	.200		-7	.447	-20	.100
-2	.794	-15	.178		-8	.398	-30	.032
-3	.707	-16	.158		-9	.355	-40	.010
-4	.631	-17	.141		-10	.316	-50	.003
-5	.562	-18	.125		-11	.282	-60	.001
					-12	.250	-80	.000

Return Loss

Return Loss is the measurement (in dB) of the amount of signal that is reflected back toward the transmitter. The reflection of the signal is caused by the variations of impedance in the connectors and cable and is usually attributed to a poorly terminated wire. The greater the variation in impedance, the greater the return loss reading. If 3 pairs of wire pass by a substantial amount, but the 4 pair barely passes, it usually is an indication of a bad crimp or bad connection at the RJ45 plug. Return loss is usually not significant in the loss of a signal, but rather signal jitter.

Near-End Crosstalk (NEXT)

Near-End Crosstalk (NEXT) is an error condition that describes the occurrence of a signal from one wire pair radiating to and interfering with the signal of another wire pair. It is the difference in amplitude (in dB) between a transmitted signal and the crosstalk received on other cable pairs at the same end of the cabling. Higher NEXT values correspond to better cabling performance. A higher value is desirable as it would indicate that the power transmitted is greater in magnitude than the power induced onto another wire pair given that the NEXT measurement is simply a difference calculation. NEXT must be measured from each pair to each other pair in twisted pair cabling and from each end of the connection. NEXT is measured 30 meters (about 98 feet) from the injector / generator. Lower near end crosstalk values correspond to higher overall circuit performance. High NEXT values on a UTP LAN that will be using an older signaling standard (IEEE 802.3i and earlier) are particularly detrimental. It could be an indication of improper termination.

Power Sum NEXT (PSNEXT)

Power Sum NEXT (PSNEXT) is the sum of NEXT values from 3 wire pairs as they affect the other wire pair. The combined effect of NEXT can be very detrimental to the signal.

The Equal-Level Far-End Crosstalk (ELFEXT)

The Equal-Level Far-End Crosstalk (ELFEXT) test measures Far-End Crosstalk (FEXT). FEXT is very similar to NEXT, but happens at the receiver side of the connection. Due to impedance on the line, crosstalk diminishes the signal as it gets further away from the transmitter. Because of this, FEXT is usually less detrimental to a signal than NEXT, but still important nonetheless.

Power Sum ELFEXT (PSELFEXT)

Power Sum ELFEXT (PSELFEXT) is the sum of FEXT values from 3 wire pairs as they affect the other wire pair.

Attenuation-to-Crosstalk ratio (ACR)

Attenuation-to-Crosstalk ratio (ACR) is the difference between the signal attenuation produced and NEXT and is measured in decibels (dB). The ACR indicates how much stronger the attenuated signal is than the crosstalk at the destination (receiving) end of a communications circuit. The ACR figure must be at least several decibels for proper performance. If the ACR is not large enough, errors will be frequent. In many cases, even a small improvement in ACR can cause a dramatic reduction in the bit error rate. Sometimes it may be necessary to switch from un-shielded twisted pair (UTP) cable to shielded twisted pair (STP) in order to increase the ACR.

Power Sum ACR (PSACR)

Power Sum ACR (PSACR) done in the same way as ACR, but using the PSNEXT value in the calculation rather than NEXT.

DC Loop Resistance

DC Loop Resistance measures the total resistance through one wire pair looped at one end of the connection. This will increase with the length of the cable. DC resistance usually has less effect on a signal than insertion loss, but plays a major role if power over Ethernet is required. Also measured in ohms is the characteristic impedance of the cable, which is independent of the cable length.

Copper Cable Certification

Copper Cable Certification

In copper twisted pair wire networks, copper cable certification is achieved through a thorough series of tests in accordance with Telecommunications Industry Association (TIA) or International Organization for Standardization (ISO) standards. These tests are done using a certification-testing tool, which provide “Pass” or “Fail” information. While certification can be performed by the owner of the network, certification is primarily done by datacom contractors. It is this certification that allows the contractors to warranty their work.

Need for certification

Installers who need to prove to the network owner that the installation has been done correctly and meets TIA or ISO standards need to certify their work. Network owners who want to guarantee that the infrastructure is capable of handling a certain application (e.g. Voice over Internet) will use a tester to certify the network infrastructure. In some cases, these testers are used to pinpoint specific problems. Certification tests are vital if there is a discrepancy between the installer and network owner after an installation has been performed.

The Standards

The performance tests and their procedures have been defined in the ANSI/TIA/EIA-568-B.1 standard and the ISO/IEC 11801 standard. The TIA standard defines performance in categories (Cat 3, Cat 5e, Cat 6) and the ISO defines classes (Class C, D, E, and F). These standards define the procedure to certify that an installation meets performance criteria in a given category or class.

The significance of each category or class is the limit values of which the Pass/Fail and frequency ranges are measured; Cat 3 and Class C (no longer used) test and define communication with 16 MHz bandwidth, Cat 5e and Class D with 100 MHz bandwidth, Cat 6 and Class E up to 250 MHz, and Cat 7 and Class F with a frequency range through 600 MHz.

The standards also define that data from each test result must be collected and stored in either print or electronic format for future inspection.

The Tests

Test Parameter	TIA-568-B	ISO 11801:2002
Wiremap	Pass/Fail	Pass/Fail
Propagation Delay	Pass/Fail	Pass/Fail
Delay Skew	Pass/Fail	Pass/Fail
Cable Length	Pass/Fail	Information only
Insertion Loss (IL)	Pass/Fail	Pass/Fail
Return Loss (RL)	Pass/Fail (except Cat3)	Pass/Fail
Near-End Crosstalk (NEXT)	Pass/Fail	Pass/Fail
Power Sum NEXT (PSNEXT)	Pass/Fail	Pass/Fail
Equal-Level Far-End Crosstalk (ELFEXT)	Pass/Fail	Pass/Fail
Power Sum ELFEXT (PSELFEXT)	Pass/Fail	Pass/Fail
Attenuation-to-Crosstalk Ratio (ACR)	Information only	Pass/Fail (except Class C)
Power sum ACR (PSACR)	Information only	Pass/Fail (except Class C)
DC Loop Resistance		Pass/Fail

Twisted Pair Cable (UTP), 4 pairs, Category 6, Solid, PVC

Specifications

Meet ANSI/EIA/TIA 568-B.2-1 requirements
Fire protection – IEC60332-1 (CM)
The cable meets UL 1581 VW-1 fire safety standard

Description

Unshielded copper cable, 4 pairs, category 6, solid
Cable is used for indoor installation

Materials:

Conductive material: wire made of soft annealed electrolytic copper
Conductor insulation: HDPE
The cable jacket: PVC

Technical characteristics:

Conductor diameter: 0.54 ± 0.01 mm (24 AWG)
Insulated conductor diameter: 0.99 ± 0.2 mm (0.038″ ± 0.008″)
Outer cable diameter: 6.2 ± 0.2 mm (0.24″ ± 0.008″)
Jacket thickness: 0.4 mm (0.015″)
Pulling strength: 130 N
Minimum bend radius: 4 outer cable diameters
Operating temperature: -20°C to +75°C (-4°F to +167°F)
Weight per 1000 ft: 12.9 kg (28.4 lbs)
Standard package: 305 m (1000 ft)

Electrical characteristics:

Frequency, MHz	RL	Attenuation, dB	NEXT, dB	PSNEXT, dB	ELFEXT, dB	PSELFEXT, dB
1.0	20.0	2.0	74.3	72.3	67.8	64.8
4.0	20.3	3.8	65.3	63.3	55.8	52.8
8.0	24.5	5.3	60.8	58.8	49.7	46.7
10.0	25.0	6.0	59.3	57.3	47.8	44.8
16.0	25.0	7.6	56.3	54.3	43.7	40.7
20.0	25.0	8.5	54.8	52.8	41.8	38.8
25.0	24.3	9.5	53.3	51.3	39.8	36.8
31.25	23.6	10.7	51.9	49.9	37.9	34.9
62.5	21.5	15.4	47.4	45.4	31.9	28.9
100.0	20.1	19.8	44.3	42.3	27.8	24.8
200.0	18.0	29.0	39.8	37.8	21.8	18.8
250.0	17.3	32.8	38.3	36.3	19.8	16.8

Conductor resistance at 20°C (68°F)	9.38 Ohm/100 m (2.9 Ohm/100 ft)
DC Resistance Unbalance	5%
Pair-to-Ground Capacitance Unbalance	330 pF/100 m (101 pF/100 ft)
Impedance 0.772-100 MHz	85-115 Ohm
Mutual Capacitance	5.6 nF/m (1.7 nF/ft)
Spark Test	2.5 kV

Network Cable Installations

If we have to run cables (of any type) through existing walls and ceilings, the cable installation can be the most expensive part of setting up a LAN. At every branching point, special fittings connect the intersecting wires. Sometimes, we also need various additional components along the way, such as hubs, repeaters, or MSAUs.

With the development of easy-to-build (or prebuilt) Category 5 twisted-pair cabling, high-speed and low-cost NICs and hubs, and built-in basic networking in current versions of Windows, installing and setting up a network today is far easier than ever before. For small cubicle/office networking in which no wire must be routed through walls and in which Windows peer networking software will be used, we should be able to set up the network ourself.

If our wiring must go through walls, be run through dropped ceilings, be piggybacked on air ducts, or be run between floors, we might want to have professional network-cable specialists install the cable. A good company knows the following:

• When UTP (unshielded twisted-pair) cabling is adequate
• Where STP (shielded twisted-pair) cabling might be necessary to avoid excessive cable runs and interference
• How to route cable between rooms, floors, and nonadjacent offices
• How to use wall panels to make cable attachments look better and more professional
• When we must use fireproof Plenum cable
• How to deal with sources of electrical interference, such as elevator motors, transmitters, alarm systems, and even florescent office lighting, by using fiber-optic or shielded cable

If one decides to need professional cable installation, be sure to get a firm price quote first because the cost of a complex cable installation might make a wireless network a more appealing choice.

Selecting the Proper Cable

A network is only as fast as its slowest component; to achieve the maximum speeds of the network, all its components, including cables, must meet the standards. Two standard types of twisted-pair cabling exist:

• Category 3 cable. The original type of UTP cable used for Ethernet networks was also the same as that used for business telephone wiring. This is known as Category 3, or voice-grade UTP cable, and is measured according to a scale that quantifies the cable’s data-transmission capabilities. The cable itself is 24 AWG (American Wire Gauge, a standard for measuring the diameter of a wire), copper-tinned with solid conductors, 100–105 ohm characteristic impedance, and a minimum of two twists per foot. Category 3 cable is adequate for networks running at up to 16Mbps. This cable usually looks like “silver” telephone cable, but with the larger RJ-45 connector. Category 3 cabling is obsolete because it doesn’t support Fast Ethernet or greater network speeds.
• Category 5 cable. The newer, faster network types require greater performance levels. Fast Ethernet (100BASE-TX) uses the same two-wire pairs as 10BASE-T, but Fast Ethernet needs a greater resistance to signal crosstalk and attenuation. Therefore, the use of Category 5 UTP cabling is essential with 100BASE-TX Fast Ethernet. Although the 100BASE-T4 version of Fast Ethernet can use all four-wire pairs of Category 3 cable, this flavor of Fast Ethernet is not widely supported and has practically vanished from the marketplace. Thus, for practical purposes, if one mixes Category 3 and Category 5 cables, one should use only 10BASE-T (10Mbps) Ethernet hubs; if we try to run Fast Ethernet 100BASE-TX over Category 3 cable, we will have a slow and unreliable network. Category 5 cable is commonly called CAT5 and is also referred to as Class D cable.

Many cable vendors also sell an enhanced form of Category 5 cable called Category 5e (specified by Addendum 5 of the ANSI/TIA/EIA-568-A cabling standard). Category 5e cable can be used in place of Category 5 cable and is especially well suited for use in Fast Ethernet networks that might be upgraded to Gigabit Ethernet in the future. Category 5e cabling must pass several tests not required for Category 5 cabling. Even though we can use both Category 5 and Category 5e cabling on a Gigabit Ethernet network, Category 5e cabling provides better transmission rates and a greater margin of safety for reliable data transmission.

Category 6 cabling (also called CAT 6 or Class E) can be used in place of CAT 5 or 5e cabling and uses the same RJ-45 connectors as CAT 5 and 5e. CAT 6 cable handles a frequency range of 1MHz–250MHz, compared to CAT5 and CAT5e’s 1MHz–100MHz frequency range.

One should use existing Category 3 cable for our LAN only if we are content with the 10Mbps speeds of 10BASE-T and if the cable is in good condition. The silver exterior on Category 3 cabling can become brittle and deteriorate, leading to frequent network failures. If we are installing new wiring for a new network or replacing deteriorated Category 3 cable, we should use Category 5, Category 5e, or Category 6 cabling. All three types are widely available either in prebuilt assemblies or in bulk.

The newest standard—Category 7 cabling (also called CAT 7 or Class F)—handles a frequency range of 1MHz–600MHz and reduces propagation delay and delay skew, which enables longer network cables and larger numbers of workstations on a network. CAT 7 uses the GG45 connector developed by Nexans. The GG45 connector resembles the RJ-45 connector but has four additional contacts. GG45 connector contains a switch that activates a maximum of 8 out of 12 contacts. The upper 8 RJ45 contacts are used for up to 250MHz (CAT 6) operation, whereas the 8 contacts in the outer edges are used for 600MHz (CAT 7) operation. Only 8 contacts are used at a given time. In other words, this connector is designed to be backward-compatible with cables using RJ-45 connectors, while supporting the newer standard.

Choosing the correct type of Category 5/5e cable is also important. Use solid PVC cable for network cables that represent a permanent installation. However, the slightly more expensive stranded cables are a better choice for a notebook computer or temporary wiring of no more than 10″ lengths (from a computer to a wall socket, for example) because it is more flexible and is therefore capable of withstanding frequent movement.

If we plan to use air ducts or suspended ceilings for cable runs, we should use Plenum cable, which doesn’t emit harmful fumes in a fire. It is much more expensive, but the safety issue is a worthwhile reason to use it (and it is required by some localities).

Building Own Twisted-Pair Cables

When it’s time to wire our network, we have two choices. We can opt to purchase prebuilt cables, or we can build our own cables from bulk wire and connectors.

We should build our own twisted-pair cables if we:

• Plan to perform a lot of networking
• Need cable lengths longer than the lengths you can buy preassembled at typical computer departments
• Want to create both standard and crossover cables
• Want to choose our own cable color
• Want maximum control over cable length
• Want to save money
• Have the time necessary to build cables

TP Wiring Standards

If we want to create twisted-pair (TP) cables ourself, be sure our cable pairs match the color-coding of any existing cable or the color-coding of any prebuilt cabling we want to add to our new network. Because there are eight wires in TP cables, many incorrect combinations are possible. Several standards exist for UTP cabling.

One common standard is the AT&T 258A configuration (also called EIA/TIA 568B). Table lists the wire pairing and placement within the standard RJ-45 connector.

RJ-45 Connector Wire Pairing and Placement for AT&T 258A/EIA 568B Standard
Wire Pairing	Wire Connected to Pin #	Pair Used For
White/blue and blue	White/blue – #5 Blue – #4	Not used[1]
White/orange and orange	White/orange – #1 Orange – #2	Transmit
White/green and green	White/green – #3 Green – #6	Receive
White/brown and brown	White/brown – #7 Brown – #8	Not used[1]

^[1] This pair is not used with 10BASE-T or Fast Ethernet 100BASE-TX, but all four pairs are used with Fast Ethernet 100BASE-T4 and Gigabit Ethernet 1000BASE-TX standards.

Crossover UTP Cables

Crossover cables, which change the wiring at one end of the cable, are used to connect two (and only two) computers together when no hub or switch is available or to connect a hub or switch without an uplink (stacking) port to another hub or switch. The pinout for a crossover cable is shown in Table. This pinout is for one end of the cable only; the other end of the cable should correspond to the standard TIA 568B pinout.

RJ-45 Connector Wire Pairing and Placement for Crossover Variation on EIA 568B Standard
Wire	Pin #	Wire	Pin #
White/blue	5	White/orange	3
Blue	4	Orange	6
White/green	1	White/brown	7
Green	2	Brown	8

Cable Distance Limitations

The people who design computer systems love to find ways to circumvent limitations. Manufacturers of Ethernet products have made possible the building of networks in star, branch, and tree designs that overcome the basic limitations already mentioned. We can have thousands of computers on a complex Ethernet network.

LANs are local because the network adapters and other hardware components typically can’t send LAN messages more than a few hundred feet. Table lists the distance limitations of various types of LAN cable. In addition to the limitations shown in the table, keep the following points in mind:

• We can’t connect more than 30 computers on a single Thinnet Ethernet segment.
• We can’t connect more than 100 computers on a Thicknet Ethernet segment.
• We can’t connect more than 72 computers on a UTP Token-Ring cable.
• We can’t connect more than 260 computers on an STP Token-Ring cable.

Network Distance Limitations
Network Adapter	Cable Type	Maximum	Minimum
Ethernet	10BASE-210BASE-5 (drop) 10BASE-5 (backbone) 10BASE-T 100BASE-TX 1000BASE-TX	185m (607 ft.)50m (164 ft.) 500m (1,640 ft.) 100m (328 ft.) 100m (328 ft.) 100m (328 ft.)	0.5m (1.6 ft.)2.5m (8.2 ft.) 2.5m (8.2 ft.) 2.5m (8.2 ft.) 2.5m (8.2 ft.) 2.5m (8.2 ft.)
Token-Ring	STPUTP	100m (328 ft.)45m (147 ft.)	2.5m (8.2 ft.)2.5m (8.2 ft.)
ARCnet	Passive hub dropActive hub	30m (98 ft.)600m (1,968 ft.)	Varies by cable typeVaries by cable type

If we have a station wired with Category 5 cable that is more than 328 feet (100 meters) from a hub, we must use a repeater. If we have two or more stations beyond the 328″ limit of UTP Ethernet, connect them to a hub or switch that is less than 328 feet away from the primary hub or switch and connect the new hub or switch to the primary hub or switch via its uplink port. Because hubs and switches can act as repeaters, this feature enables us to extend the effective length of the network.

Category 6 Specifications

1) Construction –

• Conductor: 24 AWG 7/32 Tinned Copper
• Insulation: High Density Polyethylene. .007″ Nom. Wall Thickness
• Pairs: Color coded singles twisted into pairs
• Cable: (4) Twisted Pairs twisted together to form a cable core
• Jacket: Polyvinylchloride, Black, .020″ Nom. Wall Thickness

2) Physical Properties –

• Temperature Rating, Max.: 60 & 75 Degrees C
• Wt./M, Nom., Net. 22.2 LBs.

3) Electrical Characteristics (For 100m of cable) –

• Capacitance, Mutual: 13.5 PF/FT. At 1 Mhz
• Dielectric Withstanding, Min.: 1500V RMS
• Voltage Rating, Max.: 300V
• D.C. Resistance, Max.: 26.0 Ohms
• Impedance: 100+/- 15 Ohms 1-100Mhz; 100+/-20 Ohms 100 To 350 Mhz
• Impedance, Smoothed: 100 +/1 3 Ohms Typical 5 – 250 Mhz
• SRL: 23 DB 1-20 Mhz, 23 – 10 LOG(F/20) 20-100 Mhz
• Return Loss:
  • 1 – 10 Mhz: 20 + 5 LOG (F) DB Min
  • 10 – 20 Mhz: 25 DB Min
  • 20 – 250 Mhz: 25 – 8.6 LOG(F/20) DB Min
• PS NEXT: 1 – 250 Mhz = 74 – 15 LOG (F/.772) Min
• NEXT: 1 – 250 Mhz = 76 – 15 LOG (F/.772) Min
• PS ELFEXT: 1 – 250 Mhz = 67 – 20 LOG (F/.772) Min
• ELFEXT: 1 – 250 Mhz = 70 – 20 LOG (F/.772) Min
• ATTENUATION: 1 – 250 Mhz = 1.2[1.82 SQRT(F) + .017(F) + .17/SQRT(F)]MAX
• DELAY: 1 – 250 Mhz = 534 + 36/SQRT(F)
• DELAY SKEW: 1 – 100 Mhz = <25NS
• LCL: 1 – 250 Mhz = -38dB MIN

4) Agency Approvals –

• (UL) Type CM (CMR Available)
• CSA Type CMG

5) Application –

• Suitable for future applications and protocols beyond 1000Base-T (Gigabit Ethernet.)
• Cable fits standard modular plugs

6) Print –

• TIA/EIA and ISO Compliant Patch Cord / Jumper (UL) Type CM
• 24 Awg 75c – CSA LL51726 Type CMG – Category 6 (Sequential Footage)

7) Color Code –

• White/Green X Green
• White/Brown X Brown
• White/Orange X Orange
• White/Blue X Blue

Reference:

http://www.pacificcable.com/Cat_6_Tutorial.htm

Brief Overview of UTP cables

Category 5 Cable (UTP) (Unshielded Twisted Pair)

• A multipair, (usually 4 pair) high performance cable that consists of twisted pair conductors, used mainly for data transmission.
• The twisting of the pairs gives the cable a certain amount of immunity from the infiltration of unwanted interference.
• Category-5 UTP cabling systems are by far, the most common (compared to SCTP) in the United States.
• Basic cat 5 cable was designed for characteristics of up to 100 MHz.
• Category 5 cable is typically used for Ethernet networks running at 10 or 100 Mbps.

Category 5 E Cable (enhanced)

• Same as Category 5, except that it is made to somewhat more stringent standards.
• The Category 5 E standard is now officially part of the 568A standard.
• Category 5 E is recommended for all new installations, and was designed for transmission speeds of up to 1 gigabit per second (Gigabit Ethernet).

Category 6

• Same as Category 5 E, except that it is made to a higher standard.
• The Category 6 standard is now officially part of the 568A standard.

Category 7

• Same as Category 6, except that it is made to a higher standard.
• The Category 7 standard is still in the works (as of this writing) and is not yet part of the 568A standard.
• One major difference with category 7’s construction (as compared with category 5, 5 E, and 6) is that all 4 pairs are individually shielded, and an overall shield enwraps all four pairs.
• Category 7 will use an entirely new connector (other than the familiar RJ-45).

Category 5 Cable (SCTP) (Screened Twisted Pair)

• Same as above, except that the twisted pairs are given additional protection from unwanted interference by an overall shield.
• There is some controversy concerning which is the better system (UTP or SCTP).
• Category 5 SCTP cabling systems require all components to maintain the shield, and are used almost exclusively in European countries.

Category 5E, RJ45 jack (Work Area Outlet)

• An 8 conductor, compact, modular, female jack that is used to terminate category-5E cable at the user (or other) location.
• The jack is specifically engineered to maintain the performance of cat 5E cabling.

Category 5E Patch Panel

• A Category 5E Patch Panel is basically just a series of many category-5E jacks, condensed onto a single panel.
• Common panel configurations are 12, 24, 48, and 96 ports.
• Patch panels are typically used where all of the horizontal cable sections meet, and are used to connect the segments to the Network Hub.

Category 5E Patch Cable

• A Category 5E Patch Cable consists of a length of cat 5E cable with an RJ-45 male connector, crimped onto each end.
• The cable assembly is used to provide connectivity between any two category-5E female outlets (jacks).
• The two most common are from hub to patch panel, and work area outlet (jack) to the computer.

EIA/TIA 568A Standard

• This standard was published in July of 1991.
• The purpose of EIA/TIA 568A was to create a multiproduct, multivendor, standard for connectivity.
• Prior to the adoption of this standard, many “proprietary” cabling systems existed. This was very bad for the consumer.
• Among other things, the standard set the minimum requirements for category 5E cable and hardware.
• The 568 “standard” is not to be confused with 568A or 568B wiring schemes, which are themselves, part of the “568A standard”.

568A and 568B Wiring Schemes

• When we refer to a jack or a patch panel’s wiring connection, we refer to either the 568A, or 568B wiring scheme, which dictates the pin assignments to the pairs of cat 5E cable.
• It is very important to note that there is no difference, whatsoever, between the two wiring schemes, in connectivity or performance when connected form one modular device to another (jack to Patch panel, RJ-45 to RJ-45, etc.), so long as they (the two devices) are wired for the same scheme (A or B).
• The only time when one scheme has an advantage over the other, is when one end of a segment is connected to a modular device, and the other end to a punch block. In which case, the 568A has the advantage of having a more natural progression of pairs at the punch block side.

Four Pairs

Pair 1: White / Blue

Pair 2: White / Orange

Pair 3: White / Green

Pair 4: White / Brown

Wiremap

• This is the most basic test that can be performed on a category-5E segment.
• Wiremap tests for the basic continuity between the two devices.
• In 568A or B, all eight pins of each device should be wired straight through (1 to 1, 2 to 2, 3 to 3, etc.).
• A wiremap (continuity) test should also test for absence of shorts, grounding, and external voltage.

Crosstalk

• Crosstalk is the “bleeding” of signals carried by one pair, onto another pair through the electrical process of induction (wires need not make contact, signals transferred magnetically).
• This is an unwanted effect that can cause slow transfer, or completely inhibit the transfer of data signals over the cable segment.
• The purpose of the wire twists, in category 5E cable is to significantly reduce the crosstalk, and its effects.
• Two types are: NEXT (Near End Crosstalk), and FEXT (Far End Crosstalk).
• Fiber Optic cable is the only medium that is 100% immune to the effects of crosstalk.

Ambient Noise or Electromagnetic Interference (EMI)

• Similar to crosstalk, in that it is an unwanted signal that is induced into the cable.
• The difference is that ambient noise (or EMI) is typically induced from a source that is external to the cable.
• This could be an electrical cable or device, or even an adjacent category 5E cable.

Attenuation

• Attenuation is the loss of signal in a cable segment due to the resistance of the wire plus other electrical factors that cause additional resistance (Impedance and Capacitance for example).
• A longer cable length, poor connections, bad insulation, a high level of crosstalk, or ambient noise, will all increase the total level of attenuation.
• The 568A standard specifies the maximum amount of attenuation that is acceptable in a category-5E cable segment.

Reference:

http://www.hochien.com/data1/5E%20&%20Cat%206%20Cabling%20Tutorial%20and%20FAQ’s.pdf

Cable Installation: Do’s and Don’ts

Do	Run all cables in a “Star” configuration. That is to say that they all emanate from, and are “home run” to, one central location, known as the wiring hub. Visualize a wagon wheel, all of the spokes, start from on central point, known as the hub of the wheel
Do	Keep all cable runs to a maximum of 295 feet (for each run)
Do	Maintain the twists of the pairs all the way to the point of termination, or no more than 0.5″ (one half inch) untwisted
Do Not	Skin off more than 1″ of jacket when terminating
Do	Make gradual bends of the cable, where necessary. No sharper than a 1″ radius. (about the roundness of a half-dollar)
Do Not	Allow the cable to be sharply bent, or kinked, at any time. This can cause permanent damage to the cables’ interior
Do	Dress the cables neatly with cable ties. Use low to moderate pressure
Do Not	Over tighten cable ties. We recommend Hook and Loop (Velcro) Cable Ties for commercial installations
Do	Cross-connect cables (where necessary), using cat 5E rated punch blocks and components.
Do Not	Splice or bridge category-5E cable at any point. There should never be multiple appearances of category 5E cable
Do	Use low to moderate force when pulling cable
Do Not	Use excessive force when pulling cable
Do	Use cable pulling lubricant for cable runs that may otherwise require great force to install. (You will be amazed at what a difference the cable lubricant will make)
Do Not	Use oil, or any other lubricant, not specifically designed for cable pulling. Oil, or other lubricants, can infiltrate the cable, causing damage to the insulation
Do	Keep cat 5E cables as far away from potential sources of EMI (electrical cables, transformers, light fixtures, etc.) as possible
Do Not	Tie cables to electrical conduits, or lay cables on electrical fixtures
Do	Install proper cable supports, spaced no more than 5 feet apart
Do Not	Install cable that is supported by the ceiling tiles (this is unsafe, and is a violation of the building codes)
Do	Always label every termination point . Use a unique number for each cable segment. The idea here, is to make moves, adds, changes, and troubleshooting as simple as possible
Do	Always test every installed segment with a cable tester. “Toning” alone, is not an acceptable test.
Do	Always install jacks in such a way as to prevent dust and other contaminants from settling on the contacts. The contacts (pins) of the jack should face up on flush mounted plates, or left, right, or down (never up) on surface mount boxes.
Do	Always leave extra slack on the cables, neatly coiled up in the ceiling or nearest concealed place. It is recommended that you leave at least 5 feet at the work outlet side, and 10 feet at the patch panel (wiring hub) side.
Do Not	Never install cables “taught” in the ceiling, or elsewhere. A good installation should have the cables loose, but never sagging.
Do	Always use grommets to protect the cable where passing through metal studs or anything that can possibly cause damage to them.
Do	Choose either 568A or 568B wiring standard, before you begin your project. Wire all jacks and patch panels for the same wiring scheme (A or B).
Do Not	Mix 568A and 568B wiring on the same installation.
Do Not	Use staples on category-5E cable that crimp the cable tightly. The common T-18 and T-25 cable staples are not recommended for category 5E cable. The T-59 insulated staple gun is ideal for fastening cat5 & 6 and fiber optic cabling as it does not put any excess pressure on the cable.
Do	Always obey all local, and national, fire and building codes. Be sure to “fire stop” all cables that penetrate a firewall. Use plenum rated cable where it is mandated.

Category 6

Channel Configuration

UTP Category 6 Cable

Cat-6 Channel Equations

Channel Specifications

Channel Performance

Comparison of Cat-6 with other Cat-5

Cable Insertion Loss & NEXT

Channel Return Loss

Loss & Crosstalk

TIA CAT 6 Standards

• ANSI/TIA/EIA 568-B.2-1 Commercial Building Telecommunications Cabling Standard
• Part 2: Balanced Twisted-Pair Cabling Components
• Addendum 1: Transmission Performance Specifications for 4-Pair 100 Ohm Category 6 Cabling

General

The original document is an addendum to already published document(s), and because of that fact, references are made to the original specification. As an overall statement, this document specifies the requirements and specifications for Category 6 cable, cords and connecting hardware. By definition, Category 6 systems meet transmission requirements up to 250 MHz

Recognized Components

Cable

A category 6 cable is by definition a twisted pair, 100 Ohm cable which has transmission parameters specified up to 250 MHz. Category 6 cable is also a recognized cable in addition to those specified in 4.2.2 of ANSI/TIA/EIA-568-B.2.

Horizontal & Backbone Cable

Category 6 cable may be used for both horizontal and backbone cable. Recognized horizontal and backbone cable shall be either 4 pair 100 Ohm UTP, or ScTP, consisting of 22 AWG or 24 AWG solid conductors individually insulated by a thermoplastic material and then formed into 4 twisted pairs with an overall thermoplastic jacket. The cable shall meet the requirements of ANSI/ICEA S-80-576 applicable to four-pair inside wiring cable for plenum or general cabling within a building, ANSI/ICEA S-90-661-1994. Horizontal cable shall also meet the requirements of clauses 4.3.3.1 to 4.3.3.6 of ANSI/TIA/EIA-568-B.2. Backbone cable shall meet the requirements of clauses 4.4.3.1 to 4.4.3.6 of ANSI/TIA/EIA-568-B.2.

Note

Additional requirements for 100 Ohm ScTP cables are located in annex K of the original ANSI/TIA/EIA-568-B.2 standard.

Bundled & Hybrid Cable

Bundled and hybrid cables may be used for horizontal and backbone cabling provided that each cable type is meets the requirements of clause 6.1.1 of this Standard and clause 4.4 of ANSI/TIA/EIA-568-B.1. The cable must also meet the transmission and color-code specifications for that cable type as given in ANSI/TIA/EIA-568-B.2, ANSI/TIA/EIA-568-B.3, and clause 7 in the original documentation of this standard. The cable must also meet total power sum NEXT loss requirements. The original standard outlines the equation required for calculation of NEXT.

Connecting Hardware & Cords

Connecting hardware and cords meeting transmission characteristics from 1 Mhz to 250 Mhz are recognized under this standard. In addition patch cords and cordage must also meet the requirements of clauses 6.1 through 6.3 of ANSI/TIA/EIA-568-B.2 and clause 7.2.1.3 and 7.4.4 of the original standards documentation.

Transmission Requirements

Category 6 Cable Transmission Parameters

Standards Preservation

Frequency (MHz)	0.772	1.0	4.0	8.0	10.0	16.0	20.0	25.0	31.25	62.5	100.0	200.0	250.0
Insertion Loss (Solid)	1.8	2.0	3.8	5.3	6.0	7.6	8.5	9.5	10.7	15.4	19.8	29.0	32.8
Insertion Loss (Stranded)	–	2.4	4.5	6.4	7.1	9.1	10.2	11.4	12.8	18.5	23.8	34.8	39.4
NEXT (Worst pair to pair)	76.0	74.3	65.3	60.8	59.3	56.2	54.8	53.3	57.9	47.4	44.3	39.8	38.3
Power Sum NEXT	74.0	72.3	63.3	58.8	57.3	54.2	52.8	51.3	49.9	45.4	42.3	37.8	36.3
ELFEXT (Worst pair to pair)	70.0	67.8	55.8	49.7	47.8	43.7	41.8	39.8	37.9	31.9	27.8	21.8	19.8
Power Sum ELFEXT	67.0	64.8	52.8	46.7	44.8	40.7	38.8	36.8	34.9	28.9	24.8	18.8	16.8
Return Loss (Solid)	–	20.0	23.0	24.5	25.0	25.0	25.0	24.3	23.6	21.5	20.1	18.0	17.3
Return Loss (Stranded)	–	20.0	23.0	24.5	25.0	25.0	25.0	24.2	23.3	20.7	19.0	16.4	15.6
LCL	–	40.0	40.0	40.0	40.0	38.0	37.0	36.0	35.1	32.0	30.0	27.0	26.0

Category 6 Connecting Hardware Transmission Parameters

 Standards Preservation

Frequency (MHz)	0.772	1.0	4.0	8.0	10.0	16.0	20.0	25.0	31.25	62.5	100.0	200.0	250.0
Insertion Loss	0.1	0.1	0.1	0.1	0.1	0.1	0.1	0.1	0.11	0.16	0.20	0.28	0.32
NEXT (Worst pair to pair)	–	75.0	75.0	75.0	74.0	69.9	68.0	66.0	64.1	58.1	54.0	48.0	46.0
FEXT	–	75.0	71.1	65.0	63.1	59.0	57.1	55.1	53.2	47.2	46.1	37.1	35.1
Return Loss	–	30.0	30.0	30.0	30.0	30.0	30.0	30.0	30.0	28.1	24.0	18.0	16.0
LCL	–	40.0	40.0	40.0	40.0	40.0	40.0	40.0	38.1	32.1	28.0	22.0	20.0
Work Area Cords	–	19.8	21.6	22.5	22.8	23.4	23.7	24.0	23.0	20.0	18.0	15.0	14.0

Category 6 Permanent Link Transmission Parameters

Standards Preservation

Frequency (MHz)	0.772	1.0	4.0	8.0	10.0	16.0	20.0	25.0	31.25	62.5	100.0	200.0	250.0
Insertion Loss	–	1.9	3.5	5.0	5.5	7.0	7.9	8.9	10.0	14.4	18.6	27.4	31.1
NEXT (Worst pair to pair)	–	65.0	64.1	59.4	57.8	54.6	53.1	51.5	50.0	45.1	41.8	36.9	35.3
Power Sum NEXT	–	62.0	61.8	57.0	55.5	52.2	50.7	49.1	47.5	42.7	39.3	34.3	32.7
ELFEXT (Worst pair to pair)	–	64.2	52.1	46.1	44.2	40.1	38.2	36.2	34.3	28.3	24.2	18.2	16.2
Power Sum ELFEXT	–	61.2	49.1	43.1	41.2	37.1	35.2	33.2	31.3	25.3	21.2	15.2	13.2
Return Loss	–	19.1	21.0	21.0	21.0	20.0	19.5	19.0	18.5	16.0	14.0	11.0	10.0

Category 6 Channel Transmission Parameters

Standards Preservation

Frequency (MHz)	0.772	1.0	4.0	8.0	10.0	16.0	20.0	25.0	31.25	62.5	100.0	200.0	250.0
Insertion Loss	–	2.1	4.0	5.7	6.3	8.0	9.0	10.1	11.4	16.5	21.3	31.5	35.9
NEXT (Worst pair to pair)	–	65.0	63.0	58.2	56.6	53.2	51.6	50.0	48.4	43.4	39.9	34.8	33.1
Power Sum NEXT	–	62.0	60.5	55.6	54.0	50.6	49.0	47.3	45.7	40.6	37.1	31.9	30.2
ELFEXT (Worst pair to pair)	–	63.3	51.2	45.2	43.3	39.2	37.2	35.3	33.4	27.3	23.3	17.2	15.3
Power Sum ELFEXT	–	60.3	48.2	42.2	40.3	36.2	34.2	32.3	30.4	24.3	20.3	14.2	12.3
Return Loss	–	19.0	19.0	19.0	19.0	18.0	17.5	17.0	16.5	14.0	12.0	9.0	8.0

General

For each transmission parameter where applicable, the cable, connecting hardware and cords are tested for the parameter under the following categories:

• Individual test parameter for cable
• Individual test parameter for connecting hardware
• Permanent Link
• Channel
• Work Area Cords, Patch Cords and Equipment Cords

In order to calculate the results, an equation is published in the original standards documentation detailing the parameters and conditions for each calculation, eg: temperature. In order to accurately determine the transmission results for each parameter, the equation calculation should be used. However, for standardization and comparison purposes, the results at various frequencies are documented in chart form at the end of the section.

The original standards documents also refer to the various test and measurement methods. Again, for the purposes of this document, it is assumed that the manufacturers have conformed to the proper test and measurement methods.

Insertion Loss

Insertion loss was previously referred to as attenuation, which is the change in signal strength as the signal propagates down the media. Insertion loss is a measure of the signal loss resulting from the insertion of cabling or a component between a transmitter and receiver. Insertion loss is the ratio of signal power at the receiver end to the input power determined from measured voltages, expressed in dB.

Insertion loss can be calculated by using the equation found in the original standards documentation and shall meet the values for all frequencies from 1 MHz to 250 Mhz as it pertains to:

• Cable Insertion Loss for solid and stranded cable
• Connecting Hardware Insertion Loss
• Channel Insertion Loss
• Permanent Link Insertion Loss

Notes

1. A 20 % increase in insertion loss is allowed over category 6 horizontal cable insertion loss for work area and patch cords.
2. The insertion loss of the channel or permanent link does not take into consideration the 0.1 dB measurement floor of the connecting hardware insertion loss requirement.
3. The channel insertion loss requirement is derived using the insertion loss contribution of 4 connections.
4. For the purposes of field measurements, calculated channel limits that result in insertion loss values less than 3 dB revert to a requirement of 3 dB maximum (see ANSI/TIA/EIA-568-B.2-3).
5. The permanent link insertion loss requirement is derived using the insertion loss contribution of 3 connections.
6. The maximum value for insertion loss cannot exceed .10 dB.

Near End Cross Talk (NEXT) & Power Sum Near End Cross Talk (PSNEXT) Loss

NEXT loss is a measure in dB of the unwanted signal coupling from a transmitter at the near-end into neighboring pairs, measured at the near-end. An example of cross talk is hearing a second conversation over a phone line while you are talking on the same line. In data communications, having an unwanted signal on a cable can cause network transmission problems. NEXT loss is expressed relative to the transmit signal level.

Pair to Pair NEXT can be calculated by using the equation found in the original standards documentation and shall meet the values for all frequencies from .772 MHz to 250 MHz. The worst pair to pair result is shown to ensure all pair to pair combinations meet the transmission requirements.

Near End Cross Talk is shown for:

• Cable NEXT
• Connecting Hardware NEXT
• Permanent Link NEXT
• Channel NEXT

Power Sum Near End Cross Talk is the calculated value of NEXT on one pair of conductors at the near end from all other energized conductor pairs at the near end. The original standards documentation provides the calculation procedures for calculating PSNEXT.

Power Sum NEXT is calculated for:

• Cable
• Permanent Link
• Channel

Connecting hardware NEXT loss shall be measured for all pair combinations in accordance with annex E. Modular plug cord NEXT loss shall be measured for all pair combinations in accordance with annex J.

Cabling Pair-to-Pair Channel & Permanent Link NEXT loss

For all frequencies from 1 MHz to 250 MHz, category 6 channel and permanent link pair-to-pair NEXT loss shall meet the values determined using the equations available in the original standards documentation. The maximum value for NEXT loss values shall not be greater than 65 dB for pair to pair measurements, and 62dB for channel.

Cable Power Sum NEXT Loss

For all frequencies from 0.772 MHz to 250 MHz, category 6 cable power sum NEXT loss, for a length of 100 m (328 ft) or longer, shall meet the values determined using the calculations found in the original standards documents.

Work Area, Equipment, & Patch Cord Pair-to-Pair NEXT Loss

Work area, equipment, and patch cords shall pass the requirements of this clause and Annex J of the original standards documentation. The original documentation provides the calculation methods for deriving the pair to pair results.

NEXT calculations take into account total NEXT for the connectors and cable used.

Notes

1. Permanent link NEXT and PSNEXT loss test limits are tougher to meet than channel NEXT and PSNEXT loss test limits. This ensures that permanent links can be converted into a channel model by using cords that meet Category 6 minimum standards.
2. A consolidation point in the permanent link may show results below the measurement accuracy for the permanent link.
3. At least a 5 m (16.4 ft) distance between the consolidation point and the telecommunications outlet connector should be maintained to help improve NEXT and PSNEXT.
4. Channel testing can be performed using cabling components that remain in place.
5. The maximum Pair to Pair NEXT value for connecting hardware shall be 75 dB.
6. The maximum value for PSNEXT is 62.0 dB.

FEXT & ELFEXT Loss

FEXT loss is a measurement in dB of the unwanted signal coupling from a transmitter at the far-end into neighboring pairs measured at the near-end. FEXT loss is the ratio of the power coupled from a disturbing pair into the disturbed pair relative to the input power at the opposite end of the transmission lines determined from measured voltages. FEXT loss shall be measured for all pair combinations in accordance with annex E of the original standards documentation.

FEXT is measured for:

• Connecting Hardware

ELFEXT shall be calculated for all pair combinations of cables and cabling in accordance with annex C of ANSI/TIA/EIA-568-B.2 and the ASTM D 4566 FEXT loss measurement procedure. Connecting hardware. In addition, since each pair can be disturbed by more than one pair, power sum equal level far-end crosstalk (PSELFEXT) is also specified for cabling and cables.

ELFEXT is measured for:

• Cable
• Permanent Link
• Channel

PSELFEXT is measured for:

• Cable
• Permanent Link
• Channel

Pair-to-Pair ELFEXT

Cable pair-to-pair ELFEXT

For all frequencies from 1 MHz to 250 MHz, category 6 cable ELFEXT, for a length of 100 m (328 ft), shall meet the values determined using calculations in the original standards documentation.

Connecting Hardware Pair-to-Pair FEXT Loss

For all frequencies from 1 MHz to 250 MHz, category 6 connecting hardware FEXT loss shall meet the values determined using calculations found in the original standard documentation. The maximum FEXT value shall not exceed 75 dB.

Permanent Link & Channel Pair-to-Pair ELFEXT

For all frequencies from 1 MHz to 250 MHz, category 6 channel and permanent link ELFEXT shall meet the values determined using calculations found in the original standards documentation.

Power Sum ELFEXT (PSELFEXT)

Power sum equal level far-end crosstalk loss takes into account the combined crosstalk (calculated) value on a receive pair from all far-end disturbers operating at the same time. The power sum equal level far-end crosstalk (PSELFEXT) loss calculation is found in the original standards documentation.

Cable Power Sum ELFEXT

For all frequencies from 1 MHz to 250 MHz, category 6 cable power sum ELFEXT, for a length of 100 m (328 ft), shall meet the values determined by the equation found in the original standards documentation

Permanent Link & Channel Power Sum ELFEXT

For all frequencies from 1 MHz to 250 MHz, category 6 permanent link and channel power sum ELFEXT shall meet the values determined using the equation found in the original standards documentation.

Return Loss

Return loss is a measure of the reflected energy caused by impedance mismatches in the cabling system. An impedance mismatch occurs when one component of the system is transitioned to another; e.g.: the cable is mated to a connector. This is very important for applications that use simultaneous bi-directional transmission. Information must be able to flow down the cable in both directions with a minimal amount of impedance to ensure smooth network operation.

Return loss is the ratio of the reflected signal power to the input power determined from measured voltages, expressed in dB. Cable and cabling return loss shall be measured in accordance with annex C of ANSI/TIA/EIA-568-B.2. Connecting hardware return loss shall be measured in accordance with annex D of ANSI/TIA/EIA-568-B.2 for all pairs. Modular plug cords shall be measured in accordance with annex J for all pairs.

Return Loss is measured for:

• Stranded Cable
• Solid Cable
• Connecting Hardware
• Permanent Link
• Channel
• Patch Cords and Equipment Cords

Horizontal Cable Return Loss

For all frequencies from 1 MHz to 250 MHz, category 6 horizontal cable return loss, for a length of 100 m (328 ft), shall meet the values determined using the equation in the original standards documentation.

Stranded Conductor Cable Return Loss

For all frequencies from 1 MHz to 250 MHz, category 6 stranded patch cable return loss, for a length of 100 m (328 ft), shall meet the values determined using the equation found in the original standards documentation.

Connecting Hardware Return Loss

For all frequencies from 1 MHz to 250 MHz, category 6 connecting hardware return loss shall meet the values determined using the equation found in the original standards documentation.

Work Area, Equipment, & Patch Cord Return Loss

For all frequencies from 1 MHz to 250 MHz, category 6 work area, equipment, and patch cord return loss shall meet the values determined using the equation found in the original standards documentation.

Permanent Link & Channel Return Loss

For all frequencies from 1 MHz to 250 MHz, category 6 permanent link and channel return loss shall meet the values determined using the equation found in the original standards documentation.

Propagation Delay & Delay Skew

Propagation delay is the time it takes for a signal to travel from one end of a conducting pair in cabling, cables, or connecting hardware to the opposite end of that pair. Propagation delay skew is a measurement of the signaling delay difference from the fastest pair to the slowest. Propagation delay and propagation delay skew are expressed in nanoseconds (ns).

Cable Propagation Delay

For all frequencies from 1 MHz to 250 MHz, category 6 cable propagation delay shall meet the values determined using the equation in the original standards documentation.

Permanent Link & Channel Propagation Delay

The maximum propagation delay for a category 6 channel configuration shall be less than 555 ns measured at 10 MHz.

The maximum propagation delay for a category 6 permanent link configuration shall be less than 498ns measured at 10 MHz.

The propagation delay from each installed mated connection is assumed to not exceed 2.5 ns for all frequencies from 1 MHz to 250 MHz.

Cable Propagation Delay Skew

For all frequencies from 1 MHz to 250 MHz, category 6 cable propagation delay skew shall not exceed 45 ns/100 meters. Testing shall be conducted using a minimum 100 meters of cable.

Permanent Link & Channel Propagation Delay Skew

For purposes of determining the permanent link and channel propagation delay skew, the propagation delay skew of each installed mated connection is assumed to be no greater 1.25 ns.

The maximum propagation delay skew for a category 6 permanent link configuration shall be less than 44 ns measured at 10 MHz, and less than 50ns for a channel configuration.

Propagation Delay & Delay Skew for Category 6 Cable

Frequency (MHz)	1	10	100	250
Maximum Delay (ns/100 meter)	570	545	538	536
Minimum Velocity of Propagation (%)	58.5	61.1	62	62.1
Maximum Delay Skew (ns/100 Meter)	45	45	45	45

Balance

Balance ensures that unwanted signal coupling modes are minimized and is related to the emission and immunity characteristics of the cabling. Balance parameters such as Longitudinal Conversion Loss (LCL) and Transverse Conversion Loss (TCL) are expressed in dB as the ratio of the signal measured at the device under test (DUT) output port relative to the signal entering the DUT input port. LCL should be measured for all cable and connecting hardware pairs in accordance with annex D found in the original standards documentation.

Note

Measurements of LCL and TCL are reciprocal due to symmetry.

Cable & Connecting Hardware LCL

For all frequencies from 1 MHz to 250 MHz, category 6 cable and connecting hardware LCL should meet the values determined using the equation found in the original standards documentation. Any calculations that result in LCL values greater than 40 dB should be shown to be 40 dB minimum.

Longitudinal Conversion Transfer Loss (LCTL)

LCTL for both cable and connecting hardware is currently under review.

Reference:

www.tiaonline.org

 

Copper Wire and Its Limitations

Due to the electrical properties of copper wiring, data signals will undergo some corruption during their travels.Signal corruption within certain limits is acceptable, but if the electrical properties of the cable will cause serious distortion of the signal, that cable must be replaced or repaired.

As a signal propagates down a length of cable, it loses some of its energy. So, a signal that starts out with a certain input voltage, will arrive at the load with a reduced voltage level. The amount of signal loss is known as attenuation, which is measured in decibels, or dB. If the voltage drops too much, the signal may no longer be useful.

Attenuation has a direct relationship with frequency and cable length. The high frequency used by the network, the greater the attenuation. Also, the longer the cable, the more energy a signal loses by the time it reaches the load.

A signal losses energy during its travel because of electrical properties at work in the cable. For example, every conductor offers some dc resistance to a current (sometimes called copper losses). The longer the cable, the more resistance it offers.

Resistance reduces the amount of signal passing through the wires – it does not alter the signal. Reactance, inductive or capacitive, distorts the signal.

The two concerns of signal transmission are:

1. That enough signal gets through. (Quantity)
2. That the signal is not distorted. (Quality)