Friday, November 20, 2009

Our Purpose...

CableNet Services Unlimited, Inc. is a fast growing telecommunication products and services company; which is determined to become the market leader thru it's innovation, motivation,process improvement and customer service.

Our Core Values...

The core values listed below serves as the philosophy that CableNet Services Unlimited Inc. expects from every employee throughout the organization.

• Understand and respect each customer
• Continuous Improvement of our processes and services
• Integrity in all we do
• Respect to our fellow employees
• Commitment to quality service at all times

Tuesday, October 20, 2009

How to Make a Network Cable :-

The steps below are general Ethernet Category 5 (commonly known as Cat 5) cable construction guidelines. For our example, we will be making a Category 5e patch cable, but the same general method will work for making any category of network cables.


STEPS:-

1. Unroll the required length of network cable and add a little extra wire, just in case. If a boot is to be fitted, do so before stripping away the sleeve and ensure the boot faces the correct way.



2. Carefully remove the outer jacket of the cable. Be careful when stripping the jacket as to not nick or cut the internal wiring. One good way to do this is to cut lengthwise with snips or a knife along the side of the cable, away from yourself, about an inch toward the open end. This reduces the risk of nicking the wires' insulation. Locate the string inside with the wires, or if no string is found, use the wires themselves to unzip the sheath of the cable by holding the sheath in one hand and pulling sideways with the string or wire. Cut away the unzipped sheath and cut the twisted pairs about 1 1/4" (30 mm). You will notice 8 wires twisted in 4 pairs. Each pair will have one wire of a certain color and another wire that is white with a colored stripe matching its partner (this wire is called a tracer).




3. Inspect the newly revealed wires for any cuts or scrapes that expose the copper wire inside. If you have breached the protective sheath of any wire, you will need to cut the entire segment of wires off and start over at step one. Exposed copper wire will lead to cross-talk, poor performance or no connectivity at all. It is important that the jacket for all network cables remains intact.



4. Untwist the pairs so they will lay flat between your fingers. The white piece of thread can be cut off even with the jacket and disposed (see Warnings). For easier handling, cut the wires so that they are 3/4" (19 mm) long from the base of the jacket and even in length.





5. Arrange the wires based on the wiring specifications you are following. There are two methods set by the TIA, 568A and 568B. Which one you use will depend on what is being connected. A straight-through cable is used to connect two different-layer devices (e.g. a hub and a PC). Two like devices normally require a cross-over cable. The difference between the two is that a straight-through cable has both ends wired identically with 568A, while a cross-over cable has one end wired 568A and the other end wired 568B.[1] For our demonstration in the following steps, we will use 568B, but the instructions can easily be adapted to 568A.
• 568B - Put the wires in the following order, from left to right:


o white orange
o orange
o white green
o blue
o white blue
o green
o white brown
o brown

• 568A - from left to right: white/green, green, white/orange, blue, white/blue, orange, white/brown, brown. You can also use the mnemonic 1-2-3-6/3-6-1-2 to remember which wires are switched.










6. Press all the wires flat and parallel between your thumb and forefinger. Verify the colors have remained in the correct order. Cut the top of the wires even with one another so that they are 1/2" (12.5 mm) long from the base of the jacket, as the jacket needs to go into the 8P8C connector by about 1/8", meaning that you only have a 1/2" of room for the individual cables. Leaving more than 1/2" untwisted can jeopardize connectivity and quality. Ensure that the cut leaves the wires even and clean; failure to do so may cause the wire not to make contact inside the jack and could lead to wrongly guided cores inside the plug.



7. Keep the wires flat and in order as you push them into the RJ-45 plug with the flat surface of the plug on top. The white/orange wire should be on the left if you're looking down at the jack. You can tell if all the wires made it into the jack and maintain their positions by looking head-on at the plug. You should be able to see a wire located in each hole, as seen at the bottom right. You may have to use a little effort to push the pairs firmly into the plug. The cabling jacket should also enter the rear of the jack about 1/4" (6 mm) to help secure the cable once the plug is crimped. You may need to stretch the sleeve to the proper length. Verify that the sequence is still correct before crimping.






8. Place the wired plug into the crimping tool. Give the handle a firm squeeze. You should hear a ratcheting noise as you continue. Once you have completed the crimp, the handle will reset to the open position. To ensure all pins are set, some prefer to double-crimp by repeating this step.


9. Repeat all of the above steps with the other end of the cable. The way you wire the other end (568A or 568B) will depend on whether you're making a straight-through, rollover, or cross-over cable (see Tips)


10. Test the cable to ensure that it will function in the field. Mis-wired and incomplete network cables could lead to headaches down the road. In addition, with power-over-Ethernet (PoE) making its way into the market place, crossed wire pairs could lead to physical damage of computers or phone system equipment, making it even more crucial that the pairs are in the correct order. A simple cable tester can quickly verify that information for you. Should you not have a network cable tester on hand, simply test connectivity pin to pin.

EtherNet Switch :-






When a hub receives a packet (chunk) of data (a frame in Ethernet lingo) at one of its ports from a PC on the network, it transmits (repeats) the packet to all of its ports and, thus, to all of the other PCs on the network. If two or more PCs on the network try to send packets at the same time a collision is said to occur. When that happens all of the PCs have to go though a routine to resolve the conflict. The process is prescribed in the Ethernet Carrier Sense Multiple Access with Collision Detection (CSMA/CD) protocol. Each Ethernet Adapter has both a receiver and a transmitter. If the adapters didn't have to listen with their receivers for collisions they would be able to send data at the same time they are receiving it (full duplex). Because they have to operate at half duplex (data flows one way at a time) and a hub retransmits data from one PC to all of the PCs, the maximum bandwidth is 100 Mhz and that bandwidth is shared by all of the PC's connected to the hub. The result is when a person using a computer on a hub downloads a large file or group of files from another computer the network becomes congested. In a 10 Mhz 10Base-T network the affect is to slow the network to nearly a crawl. The affect on a small, 100 Mbps (million bits per scond), 5-port network is not as significant.

RJ-45 Connectors - Patch Cables for Category 5 Wire



Straight-Through vs. Cross-Over:-
In general, the patch cords that you use with your Ethernet connections are "straight-through", which means that pin 1 of the plug on one end is connected to pin 1 of the plug on the other end. In this particular case it is not then important to wire them as above. Pin 1 is Pin 1 etc etc. However for the sake of uniformity it may be best to wire your cables with the same color sequence. Cross-Over cables are "crossed" end to end, data cables aren't. If you have a network hub that has an uplink port on it, you do not need to make or purchase a cross-over cable. Just switch the port on the hub to the 'uplink' mode. If your hub does not have an 'uplink' port on it, the only way to cascade another hub or attach a cable modem is to use a cross-over cable. It helps for future reference to mark or attach a tag to the cross-over cable so that you do not attempt to use it as a 'normal' patch lead at some time in the future.
The only time you cross connections in 10/100BaseT is when you connect two Ethernet devices directly together without a hub. This can be two computers connected without a hub, or two hubs via standard Ethernet ports in the hubs. Then you need a "cross-over" patch cable, which crosses the transmit and receive pairs, the orange and green pairs in normal wiring. In a cross-over cable, one end is normal, and the other end has the cross-over configuration. Remember you can only network two computers together with Cat5 cable. To add any extra PC's to your network, you will require a switch or hub. The best thing to do obviously is call 3Nines and we'll take care of all of this so you don't have to!