aneka konstrusi bangunan: Februari 2013

What is the defference between Cross Cable and Straight Cable

Now days, LAN card has intelligence, so that both cables can work.
They have a feature on lots of switches and hubs etc called "auto-mdix" or "auto mdi/mdix", that is the new thing where it doesn’t matter what kind of cable you use, it will just auto detect the proper connection type no matter which cable you use.
The cable can be categorized as Cat 5, Cat 5e, and Cat 6 UTP cable. Cat 5 UTP cable can support 10/100 Mbps Ethernet network, whereas Cat 5e and Cat 6 UTP cable can support Ethernet network running at 10/100/1000 Mbps. You might hear about Cat 3 UTP cable, it's not popular anymore since it can only support 10 Mbps Ethernet network.
Straight and crossover cable can be Cat3, Cat 5, Cat 5e or Cat 6 UTP cable, the only difference is each type will have different wire arrangement in the cable for serving different purposes.
Ethernet network cables are straight and crossover cable. This Ethernet network cable is made of 4 pair high performance cable that consists of twisted pair conductors that used for data transmission. Both end of cable is called RJ45 connector.
There are two types of network cables commonly used in PC networks - Straight-through and cross-over.

Straight Cable
Usually use straight cable to connect different type of devices. This type of cable will be used most of the time and can be used to:
1) Connect a computer to a switch/hub's normal port.
2) Connect a computer to a cable/DSL modem's LAN port.
3) Connect a router's WAN port to a cable/DSL modem's LAN port.
4) Connect a router's LAN port to a switch/hub's uplink port. (Normally used for expanding network)
5) Connect two switches/hubs with one of the switch/hub using an uplink port and the other one using normal port.
If you need to check how straight cable looks like, it's easy. Both sides (side A and side B) of cable have wire arrangement with same color.

Crossover Cable
Sometimes you will use crossover cable, it's usually used to connect same type of devices. A crossover cable can be used to:
1) Connect two computers directly.
2) Connect a router's LAN port to a switch/hub's normal port. (Normally used for expanding network)
3) Connect two switches/hubs by using normal port in both switches/hubs.
In you need to check how crossover cable looks like, both side (side A and side B) of cable have wire arrangement with following different color.
This cable (either straight cable or cross cable) has total 8 wires (or we can say lines), i.e. four twisted pairs (4x2=8) with different color codes. Right now just forget about color codes. It doesn’t matter what color is given to the cable (but there is a standard).
In straight cable connectivity is like as follows
RJ451 Connected to RJ452
Pin1------------------------------------- Pin1
Pin2------------------------------------- Pin2
Pin3------------------------------------- Pin3
Pin4------------------------------------- Pin4
Pin5------------------------------------- Pin5
Pin6------------------------------------- Pin6
Pin7------------------------------------- Pin7
Pin8------------------------------------- Pin8

In cross cable connectivity is like as follows
RJ451 Connected to RJ452
Pin1------------------------------------- Pin3
Pin2------------------------------------- Pin6
Pin3------------------------------------- Pin1
Pin4------------------------------------- Pin4
Pin5------------------------------------- Pin5
Pin6------------------------------------- Pin2
Pin7------------------------------------- Pin7
Pin8------------------------------------- Pin8

Purpose of this cross cable is RX (receiving terminal) connects to TX (transmitting) of one pc to another PC and vice versa.
As we use two PCs (same devices), straight cable will connect TX to TX and RX to RX of two computers, so cross cable is required. If you use HUB or switch, then straight cable will work because it has internal arrangement like cross cable. So note that use cross cable to connect two similar devices.
A straight cable will not work to connect two computers together.
Crossover used to connect to PCs directly together, also used for connecting networking devices together like Switch to Switch etc.
Straight cables connect two DIFFERENT types of devices. Whereas crossover cables connect two of the SAME type

Now do this (if possible): connect cross cable between switch and PC and see what happens..!

	Hub	Switch	Router	Workstation
Hub	Crossover	Crossover	Straight	Straight
Switch	Crossover	Crossover	Straight	Straight
Router	Straight	Straight	Crossover	Crossover
Workstation	Straight	Straight	Crossover	Crossover

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Communication between Switches and Workstations
When a workstation connects to a LAN, it transmits data independently of the other devices connected to the LAN media. The workstation simply transmits data frames from a NIC to the network medium.
If desired, the workstation can be attached directly to another workstation by using a crossover cable. Crossover cables connect the following devices:

Workstation to workstation
Switch to switch
Switch to hub
Hub to hub
Router to router
Router to PC

Straight-through cables connect the following devices:

Switch to router
Switch to workstation or server
Hub to workstation or server

Many modern switches now automatically adjust the port pinout to support the particular cable attached, whether it is a crossover or straight-through cable.
Switches, which are Layer 2 devices, use intelligence to learn the MAC addresses of the devices that are attached to its ports. This data is entered into a switching table. After the table is complete, the switch can read the destination MAC address of an incoming data frame on a port and immediately forward it. Until a device transmits, the switch does not know its MAC address.
Switches provide significant scalability on a network. Switches are normally connected to each other by way of trunk links.

Ethernet Cable - Color Coding Diagram

The information listed here is to assist Network Administrators in the color coding of Ethernet cables. Please be aware that modifying Ethernet cables improperly may cause loss of network connectivity. Use this information at your own risk, and insure all connectors and cables are modified in accordance with standards. The Internet Centre and its affiliates cannot be held liable for the use of this information in whole or in part.

The TIA/EIA 568-A standard which was ratified in 1995, was replaced by the TIA/EIA 568-B standard in 2002 and has been updated since. Both standards define the T-568A and T-568B pin-outs for using Unshielded Twisted Pair cable and RJ-45 connectors for Ethernet connectivity. The standards and pin-out specification appear to be related and interchangeable, but are not the same and should not be used interchangeably.

Both the T-568A and the T-568B standard Straight-Through cables are used most often as patch cords for your Ethernet connections. If you require a cable to connect two Ethernet devices directly together without a hub or when you connect two hubs together, you will need to use a Crossover cable instead.

A good way of remembering how to wire a Crossover Ethernet cable is to wire one end using the T-568A standard and the other end using the T-568B standard. Another way of remembering the color coding is to simply switch the Green set of wires in place with the Orange set of wires. Specifically, switch the solid Green (G) with the solid Orange, and switch the green/white with the orange/white. Ethernet Cable Instructions: Pull the cable off the reel to the desired length and cut. If you are pulling cables through holes, its easier to attach the RJ-45 plugs after the cable is pulled. The total length of wire segments between a PC and a hub or between two PC's cannot exceed 100 Meters (328 feet) for 100BASE-TX and 300 Meters for 10BASE-T. Start on one end and strip the cable jacket off (about 1") using a stripper or a knife. Be extra careful not to nick the wires, otherwise you will need to start over. Spread, untwist the pairs, and arrange the wires in the order of the desired cable end. Flatten the end between your thumb and forefinger. Trim the ends of the wires so they are even with one another, leaving only 1/2" in wire length. If it is longer than 1/2" it will be out-of-spec and susceptible to crosstalk. Flatten and insure there are no spaces between wires. Hold the RJ-45 plug with the clip facing down or away from you. Push the wires firmly into the plug. Inspect each wire is flat even at the front of the plug. Check the order of the wires. Double check again. Check that the jacket is fitted right against the stop of the plug. Carefully hold the wire and firmly crimp the RJ-45 with the crimper. Check the color orientation, check that the crimped connection is not about to come apart, and check to see if the wires are flat against the front of the plug. If even one of these are incorrect, you will have to start over. Test the Ethernet cable. Ethernet Cable Tips: A straight-thru cable has identical ends. A crossover cable has different ends. A straight-thru is used as a patch cord in Ethernet connections. A crossover is used to connect two Ethernet devices without a hub or for connecting two hubs. A crossover has one end with the Orange set of wires switched with the Green set. Odd numbered pins are always striped, even numbered pins are always solid colored. Looking at the RJ-45 with the clip facing away from you, Brown is always on the right, and pin 1 is on the left. No more than 1/2" of the Ethernet cable should be untwisted otherwise it will be susceptible to crosstalk. Do not deform, do not bend, do not stretch, do not staple, do not run parallel with power cables, and do not run Ethernet cables near noise inducing
components.

By looking at a T-568A UTP Ethernet straight-thru cable and an Ethernet crossover cable with a T-568B end, we see that the TX (transmitter) pins are connected to the corresponding RX (receiver) pins, plus to plus and minus to minus. You can also see that both the blue and brown wire pairs on pins 4, 5, 7, and 8 are not used in either standard. What you may not realize is that, these same pins 4, 5, 7, and 8 are not used or required in 100BASE-TX as well. So why bother using these wires, well for one thing its simply easier to make a connection with all the wires grouped together. Otherwise you'll be spending time trying to fit those tiny little wires into each of the corresponding holes in the RJ-45 connector.

What are Straight and Crossover cable

Common Ethernet network cable are straight and crossover cable. This Ethernet network cable is made of 4 pair high performance cable that consists twisted pair conductors that used for data transmission. Both end of cable is called RJ45 connector. The cable can be categorized as Cat 5, Cat 5e, Cat 6 UTP cable. Cat 5 UTP cable can support 10/100 Mbps Ethernet network, whereas Cat 5e and Cat 6 UTP cable can support Ethernet network running at 10/100/1000 Mbps. You might heard about Cat 3 UTP cable, it's not popular anymore since it can only support 10 Mbps Ethernet network. Straight and crossover cable can be Cat3, Cat 5, Cat 5e or Cat 6 UTP cable, the only difference is each type will have different wire arrangement in the cable for serving different purposes. Network Cable Straight Cable You usually use straight cable to connect different type of devices. This type of cable will be used most of the time and can be used to: 1) Connect a computer to a switch/hub's normal port. 2) Connect a computer to a cable/DSL modem's LAN port. 3) Connect a router's WAN port to a cable/DSL modem's LAN port. 4) Connect a router's LAN port to a switch/hub's uplink port. (normally used for expanding network) 5) Connect 2 switches/hubs with one of the switch/hub using an uplink port and the other one using normal port. If you need to check how straight cable looks like, it's easy. Both side (side A and side B) of cable have wire arrangement with same color. Check out different types of straight cable that are available in the market here.

Crossover Cable Sometimes you will use crossover cable, it's usually used to connect same type of devices. A crossover cable can be used to: 1) Connect 2 computers directly. 2) Connect a router's LAN port to a switch/hub's normal port. (normally used for expanding network) 3) Connect 2 switches/hubs by using normal port in both switches/hubs. In you need to check how crossover cable looks like, both side (side A and side B) of cable have wire arrangement with following different color . Have a look on these crossover cables if you plan to buy one. You can also find more network cable choices and information from Comtrad Cables.