Basic Differences Between Category cat5e, cat6, cat6e and 6a Network Patch Cables ....

                         

Category 5 through 6e cables look nearly identical for everyday people and at first glance but there are some subtle differences. There are differences that are visible and others that are not.

            Common network cables, also referred to as patch cables, look all so similar to each other. It's very difficult at times to tell them apart and for novice users, it is nearly impossible.

The most important difference between the cables is the speed and distance in which they operate most effectively. Speed and distance have a direct relationship when it comes to network cables and it's these two characteristics that differentiate cabling requirements.

Differences Between Network Cables

They may all similar but there is more to the small little wires inside the plastic cover. The number of twists even make a difference in range and speed based on frequency.

Differences Between Categories of Cables : Design, Characteristics

	CAT3	CAT5	CAT5e	CAT6	CAT6e
Maximum Data Rate (1 Twisted Pair)	10 Mbps	100 Mbps	1000 Mbps	10 Gbps	10 Gbps
Maximum Frequency	16 Mhz	100 Mhz	350 Mhz	250 Mhz	750 Mhz
Typical Distance	100 m	100 m	100 m	100 m	100 m
Maximum Distance at Maximum Data Transfer Rate			50 m	55 m

UTP cat5 through cat6a

4 Separate Pairs. This is a similarity between the various cables. They all use 4 pairs of wires.

UTP and Data Rating.

UTP is an acronym for Unshielded Twisted Pair. UTP data speed are expressed in megabits per second, or Mbps. You may have seen MB/s, this expression is mega BYTES per second. Although seemingly a symantec difference, it is not. BYTES with a capitol "B" is used for writing and reading from a storage device such as a hard drive whereas mega bits wit ha lowercase "b" is used during speed or transmission of data over a medium. Category 5 UTP cable up to 100 meters is rated for wire data speeds of up to 100 Mbps. Category 5e is rated up to 1000 Mbps (1000Mbps is 1 gigabit). Category 6 cabling is backward compatible which means it can be used for 10 and 100 Mbps applications and for rated speeds up to 1000 Mbps. Cat 6 can also perform at 10GB for very short distances. Category 6a, which has a speed rating of up to 10 gigabit (or 10,000 Mbps), is beginning to become more common as the price of network cards falls. As such was the case when the shift was from 10 to 100 then 100 to 1 Gbps.

Practical Uses for 10GB Networking

I have deployed 10GB in servers intended for virtualization. Which in short means one physical server can contain many virtual Windows servers . The virtual servers all share the physical network connections on the real physical server so 10GB is very useful in such a scenario. 10 GB on a desktop is impractical and really not worth the expense. 1 GB network cards are more than enough for a single computer.

Construction, pairs or wire count is the same

Category 5, 5e, 6, 6e, and 6a UTP has four pairs of twisted wires (Category although it is not used for data and was a phone system standard created long ago before Ethernet was the "standard cabling type". The reason why each pair of wires is twisted around each other is to allow one wire to cancel out any interference in the second wire in the pair. Category 5e and CAT5 have the same basic construction including the wire type and gauge , but with higher standards in manufacturing and installation such as and the number of twists per foot of each pair. Category 6 UTP is a slightly thick wire gauge. #22 instead of the #24 gauge wire for each pair found n 5 and 5e. It contains a contains a physical separator, a plastic separator that runs the length of the cable. It looks like a plus symbol when turned and viewed from a cut side and is the separator between the four twisted pairs to reduce electromagnetic interference between the pairs and reduce data noise.

Speed vs Cost Considerations

Consider the real and not "wish list" data speed requirements of your network. A first re-action is to want CAT6a everywhere as it will provide speeds of up to 10 gigabits. However, it use widely throughout a network is not practical yet and will yield no performance in creases as desktops are still at 1 GB and also at a cost 30 percent more than a comparable CAT5e network infrastructure. Generally as I've seen in many offices and data centers, CAT5e cabling is sufficient to support many 1Gb and 100Mb networks. Especially if the network devices such as switches and routers only support data speeds of 1000 Mbps. It's nearly inconceivable as to why some people don't upgrade but I still see 10Mbps too! - it is horrible.

Connectors, Pin assignments

Cat 6a STP RJ45 Plug

Basic Differences Between Category 5 and Category 6

Connectors for cat5 and cat5e cables are very much interchangeable and actually absolutely identical, but those for cat6 have subtle yet very distict required differences that are not easily visible but can be seen if looked at closely. All connectors are however are of the type RJ45 that we commonly see connected into our desktops and will fit into RJ45-type interface ports and sockets like those on our computers, firewalls, switches, et.. Pin assignments are also unmistakely identical for all of the three cable types and for cabling and patch cords sold as cat6e. The IEEE standards committee would have found a hard sell if pin assignments had been changed because that would have meant special new switches and that would have caused every switch manufacturer to have to design new switch ports. Because of the thicker #22 conductor wiring size, connectors for cat6 cables have slightly larger holes where each of the individual wires enters the connector. More importantly, the conducting connector material (meaning the small copper connectors we see at the end of a cable buil into the plastic connector) and the details of the conductor in each connector arrangement are designed to enhance transmission to match the characteristics of the cable.

Make Your Own Patch Cables

Straight-through pin-out RJ45 Ethernet

Making your Own Cables, It's Easy, The Wire Crimper is Key

It's not as hard as it seems and you can save some money too by making your own cables. The cost of wire is bad enough but the cost of patch cables already with ends on them is so very expensive.

The pin-outs below work. I have used them to make cables. The added tool required is a wire crimper. They are not pricey either but they are an additional cost. Borrowing one for a project is better of course.

Crossover Cables - A Special Case Cable

Ethernet Network Crossover Patch Cable pin-out and Straight Through cable pin-out.

There are cables that were called "cross-over" cables. They were much more common only a few years to a decade ago. Many, if not all, modern network switches and Ethernet interfaces on routers used in homes and business for Internet access, wireless access points, etc. have built-in cross-over detection. Which means that each port can detect if it needs to change "mode" to cross-over mode.

The need for Ethernet cross-over network cables existed because switches years ago were designed with interfaces for computers, and printers, or other "end point" devices. Simply, devices that had a single interface themselves were not a switch for multiple connections. When one switch was connected to another (actually hub to hub a little further back in time), a cross-over cable was needed because both connecting devices (each switch or hub) had multiple interfaces and were devices for multiple connections.

Cross-over network cables have a slightly different pin-tout. Pins are "crossed" on the transmit and receive. It is not as complicated or hard as it seems and a cross over cable can be made just as a normal "straight through" cable can be made. Special care needs to be taken to cross the correct wires.

Detailed explanation Distribution Networks ...How do you receive electrical power at your home or office???

 How do you receive electrical power at your home or office?

                  Electricity is one of the most convenient forms of energy available today for our day to day needs. Electrical power is used for domestic lighting, heating and motive power for driving various types of loads in industries etc. Now the question is from where do we receive this power & energy? As you know, electrical power & energy is produced (or converted from one form of energy to electrical energy) at power stations. These stations are located at various places in our country and most of them are far and remote from consumer loads. The sets of equipments installed, from sources up to the consumer loads, performing the processes of generation, transmission/transformation and distribution of electrical energy, is know as an electrical power system.

This means that the generated energy has to be transferred from the sources up to the consumer loads passing a long way. The next question that comes to our mind is that, from which power station do we receive this energy?. This is rather a difficult question to answer, as all of the generating stations are interconnected to each other through transmission lines.

You also know that most generating plants in Sri Lanka (especially if they are hydroelectric) and even in other part of the world are located in remote places (eg. Laxapana, Victoria, Samanalawewa etc.) with respect to the load centres (Colombo, Galle, Kandy, Jaffna). To deliver this generated energy to the load centers, a transmission system is required.  The transmission system should be able to carry this energy reliably, and with a minimum loss, at a virtually stable voltage and frequency.

A transmission system can be broken down into three sub systems. 

They are,

            ·         Primary Transmission System (generating points to  bulk power receiving points)

            ·         Sub Transmission System (bulk power receiving points to area substations)

            ·         Distribution System (area substations to distribution substations)

We know the generated electrical energy is transmitted over long distances to reach the load centres. Generator voltages are in the range of 11 to 30 kV; higher generator voltages are difficult to achieve owing to insulation problems in the narrow confines of the generator stator.

Long distance transmission cannot be done at generator voltage levels (11-30 kV) because of the huge material requirement and the associated high Copper Loss (sometimes we call it I²R loss). Therefore, the voltage is first stepped up at the generating point using transformers, depending upon the power system and the amount of power that has to be transmitted through transmission lines. Then this power flows through the high voltage transmission lines to the load centres.

Transmission voltages worldwide range from 110 to 765 kV. One reason for using higher transmission voltages is to improve transmission efficiency. Basically, transmission of a given amount of power (at a specified power factor) requires a fixed product of voltage and line current. Thus, the higher the voltage, the lower is the current required. Lower line currents cause lower resistive losses (I²R) in the line.

For example the present Sri Lanka Primary  Transmission System consists of an island wide network of 220 kV and 132 kV transmission lines feeding several   220/33 kV and 132/33 kV bulk power receiving stations. These receiving stations are also known as grid substations.  You should always remember that when we state the voltage of a 3-phase line, we refer to the voltage between any two wires. 

At these receiving points, the voltage is stepped down to 33 kV (or 11 kV in a few cases) and fed to the Sub Transmission System for shorter transmission runs. For example, The Sri Lanka sub transmission system comprises a 33 kV network, but there are a few 11 kV sub transmission lines, mainly in urban and suburban areas. Thereafter, the voltage is further reduced to 400 V by means of distribution transformers at distribution substations located in the residential and commercial areas for distribution purposes. Elements of a typical electrical power system are show in figure 4.1.

In this session, we will study about distribution networks, i.e. the network emanating from distribution substations up to the consumers. 

Distribution substation

The necessary electrical power for the distribution network is transformed at the distribution substations. A distribution substation consists of transformers, high voltage and low voltage bus bars, feeders, circuit breakers, instrument transformers, different types of relays (such as over current, differential & earth fault relays) etc.

As we mentioned earlier, the main functions of a distribution substation are:

·         Stepping down the transmission voltage up to the distribution voltage level.

·         Distribution of power in multiple directions.

·         Disconnect and re-connect from the H/V transmission grid or L/V distribution feeders using circuit breakers.

Figure 4.2 shows a schematic diagram of a distribution substation. The voltages of lines, which leave the low voltage bus bars, are further stepped down. At the normal operating condition the low voltage bus bars are not connected to each other (i.e. bus-tie circuit breaker is opened). It reduces the short circuit current contribution during faulty conditions to the components installed in the distribution system.

Types of distribution systems:

Let us imagine that several consumer loads (fed through distribution substations) are connected to a single source (main grid substation) located in one area. What kind of a configuration can think of, for the distribution of electrical power among these consumer loads? The simplest method is to connect each consumer load to the grid substation through dedicated feeder lines. Such a network will need a large number of feeder lines to be installed between the grid substation and the consumer loads and therefore is not recommend. Instead of connecting a single consumer to a dedicated feeder, it is recommended to connect a group of consumers to each of these feeder lines thus minimizing the overall distribution cost. However, care should be taken to avoid violation of any technical constraints such as over loading of distribution lines, voltage drops etc. Since all the lines are radialy emanating from the source in this case, this type of distribution system is known as a radial main system (see fig.4.3 (a)). The radial main distribution system is the cheapest because it requires the least amount of conductors and simple line protection methods compared to the other systems available for power distribution which we will discuss later.

However, what happens if one of these radial lines goes out of service, some times we call it a “forced outage” in technical terms? Of course, the consumer (or group of consumers), connected to the feeder line will not get any electrical power. This is the main disadvantage of radial systems. Mostly, these systems are used in rural areas. How can we avoid or at least minimize feeder outages when only one source is available? If we can find a way to connect the consumers and the source in a ring, then the consumers will receive supply from both sides and even if a portion of the line is on forced outage, the system still receives supply from either side. This type of distribution system is called a ring main system and a conceptual single line diagram is as shown in fig 4.3 (b). Normally, ring main systems receive supply from multiple sources. Usually this type of system is used or recommended in areas where the higher reliability for the consumers is a requirement. As of today, most of the distribution systems are interconnected to each other, in which the ring main systems have additional interconnections between nodes (fig4.3(c)).

Overhead lines and cables

Length of an overhead transmission line changes over a wide range, from several kilometres up to hundreds of kilometres, for an underground cable it may vary from several meters up to a few kilometres. The equivalent circuit of an overhead line or an under ground cable for purposes of analysis depends on its operating voltage and the line length. The operating voltages of the distribution lines are low and the length is always short (Approximately 8~10 km. for 11~13.8 kV lines etc.) Since the operating voltage is low, the line spacing required to maintain insulation level between the conductors on overhead line at distribution voltage levels will also become less. This leads to the characteristic of line resistance to be equal or greater than to its inductive reactance. Figure 4.4 shows a typical equivalent circuit that can be assumed for a low voltage overhead line in distribution networks.

                                             Z = R + j X                                

Voltage drops in distribution networks.

Consider a case where an electrical power is delivered from a distribution substation to a consumer load. Depending on the amount of load at the consumer and the line impedance (Z=R+jX), a voltage drop (∆v = I Z) and a transmission line loss (I²R) will appear along the line. So in order to have a V_R voltage at the receiving end of a transmission line, you would require a sending end voltage of    V_R +∆v. Therefore, it is very important for us to know the voltage drop of a transmission line against the power demand and the electrical parameters of the network connected to it. Let us first consider a simple situation where a consumer receives S=P+jQ of apparent power at a power factor of Φ from a distribution substation and demands a receiving end voltage of V_R . Now, the question is what voltage we should have at the sending end (substation) in order to maintain V_Rvoltage at the receiving end. The simplified single line diagram showing the above case is as shown in fig.4.5. Let the sending end voltage be V_S. 

Usually resistance and the inductive reactance of a distribution line are of the same order or in some cases the resistance is greater than the inductive reactance. As, such the lateral part of the voltage drop component drawn in the phasor diagram can be neglected. For this reason, the voltage drop of a distribution line can be estimated by its longitudinal component as follows:

                     Example 1:

A radial main distribution network fed from a distribution sub station is as shown in figure 4.7. The length, resistance & inductive reactance per kilometre of lines, power and power factor of the loads drawn at each load location, are given. If the observed voltage at E is 11 kV, what should be the voltage at substation?

Voltage regulation in distribution networks

To understand how voltage regulation methods work, let us look at equation 4.4 again. The resistance (R) and the reactance (X) of distribution lines (sometimes we call them line parameters) are almost constant (however, these parameters can change depending on the type & length of the lines). Active power (P) in the equation (demands by the consumer) has to be delivered through the line. The voltages at the sending end (V_S)and the receiving end (V_R) can be regulated by changing the reactive power (±Q) at the receiving end. This can be done by installing capacitor banks at the places of consumption. In such a situation, the reactive power flow from the source will be reduced and the capacitor banks installed at the receiving end compensates part of reactive power required by the consumer. The amount of reactive power needed at light load and peak load periods can be calculated using equation 4.4.

Figure 4.8 (a) shows a distribution network in which several loads are connect to a radial line through transformers. The voltage profile during the period of maximum and minimum loads without capacitor banks and the voltage profile at the period of maximum load when the capacitor bank supplies the reactive power are shown in fig.4.8 (b) line 1 and 2 and fig.4.8 (b) line 3 respectively. As you can see from the diagram, the voltage drop at far end is more than its maximum permissible limit. However, when the compensation is present, reactive power flow through the line reduces and voltage at the consumer end is improved. To understand the above, let us look at an example.

Power losses

 

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