Unformatted text preview: Physical LAN Infrastructure Physical LAN Infrastructure
Creating a CAT5 cable & Troubleshooting the Physical Layer Overview Overview Quality Cabling depends on: Knowledge of Cable types, limitations Skill in use of tools Understanding of infrastructure design Detailed knowledge of wiring standards, pin designations, purposes of different wires. Knowledge of Connectors, adapters, and transceivers BASIC LAN CABLING BASIC Skills to Develop
Creating Straight and Crossover Cables
Using a Punchdown tool Installing a Patch Panel Main subject of this presentation & lab Use of a Punchdown Block Installing Wall Jacks and keystone connectors Second lab as time permits What you need What you need Knowledge of How to make cable Cat5 cable Connectors 2’ section is adequate for learning RJ45 Crimpers Tester Wire Scissors, Wire Cutters if not included in crimper tool Knowledge/Skills Needed Knowledge/Skills Needed When to make a straight cable When to make a crossover cable Know the pin outs Know the pin outs How to skillfully make the cable Practice in doing so efficiently Use of dexterity in fingers and hands Able to do it in less than 10 minutes What’s in a CAT 5 Cable? What’s in a CAT 5 Cable?
Each pair has a positive and a negative wire run. This is called differential cabling. By twisting them together, they cancel each other’s magnetic field from creating crosstalk Basics of Data Flow Basics of Data Flow Traditional broadcast networks were Simplex networks: In modern interactive networking there must be a way to both transmit and receive data Transmit data one way (like TV Broadcast) Duplex – Two way (Receive & Transmit) Half Duplex – Two way, but uses a shared wire for both receive and transmission of data Full Duplex – separate wires for receiving and transmission Ex – 10Base2 Coax Cable Cat5 Cable has separate wires to enable both transmitting and receiving transmissions simultaneously Knowledge Content: Knowledge Content: CAT5 Cabling Standards 568A 568B Chart of all the Common 568 standard wiring pin outs First Skill: How to make a First Skill: How to make a crossover cable Crossover cable crosses the transmit wire over to the receive wire at the other end of the connection This cable is used to make a connection between two identical devices such as two hosts Tra nsm it When to use a crossover cable When to use a crossover cable Crossover can also be used for two switches or anywhere else that you have two similar devices Crossover Cable (continued) Crossover Cable Note how the transmit and receive wires are connected directly to each other Step 1: Score the insulation Step 1: Score the insulation Do not score too deeply or it will cut the wires and cause shorts or breaks Most Crimpers can also be used for this Preparing the wires Preparing the wires
1. 2. 3. Untwist the wires Fan them out Organize the colors based on the 568a or 568b standard The cut should be straight The cut should be straight No more than ½ inch after the cut is done Wire scissors work best for this cut, crimpers can also be used RJ45 Connector Placement RJ45 Connector Placement Hold the connector upside down (plastic clip on bottom Turn the connector pins away from you so that you are looking into the area to insert the wires Pin 1 will be on the far left Place your cut wires into this area. Firmly Set the wires into position Firmly Set the wires into position The wires must be all the way to the end where the pins are located to ensure a good connection Check the end to see if you can spot the copper core of all eight wires Keep pushing and working the wires until you see these eight wires Once you have done that, maintain your hold on the connector and wire with one hand and insert the RJ45 into the crimper that you are holding with the other hand. Maintain your hold on the wire and Maintain your hold on the wire and connector before insertion Insert the RJ45 connector into the appropriate crimper slot firmly Using the crimper to set the pins Using the crimper to set the pins The RJ45 must be pressed all the way in till it stops. The crimper is given a solid squeeze till it cannot be squeezed further. A small snap or popping may be heard when the crimped plastic falls into position securing the insulation around the wire. What the crimper accomplishes What the crimper accomplishes The plastic plunger keeps the sheath firmly in position so as to add strength to the connection, preventing it from coming loose. If you prefer to use four wires instead of If you prefer to use four wires instead of eight, well…yes, it works, but… It will not be useful for gigabit Ethernet Some testing devices utilize all eight wires The use of eight wires strengthens the connection making it less susceptible to someone tripping over it and pulling a wire out. Testing the Cable Testing the Cable Testers can run from $50 to $5000 or more. Basic small network and home testers for less than $100 will do a nice enough job for most things Professionals buy good quality testers. They have to certify the job before the walls are constructed. Testing Cable Testing Cable Insert the cable into the two tester receptacles Allow a few seconds for it to stabilize and finish testing Depending on the tester you use, a signal or wire map will indicate whether or not your crimp worked properly In Class Lab: In Class Lab: Making Crossover Cable
Instructor Guided Lab Straight Cable Pin Outs Straight Cable Pin Outs Note that straight cable is more straight forward Except for pin outs the process is the same to make a straight cable as it is for a crossover cable Know when to use cable types Know when to use cable types Crossover is used to connect similar devices, such as one switch to another one or one pc to another pc Remember that straight through cables have the same wiring pinouts at both ends. CABLING RULES CABLING RULES 1. Use quality components and tools to construct cables. As the saying goes, "Buy Quality, Only Cry Once." 2. Under no circumstances should cable bends be less than four times the diameter of the cable. The Cat 5E standard is no bend radius less than 5 inches. 3. When bundling groups of cables together with cable ties (zip ties), keep the ties snug but not excessively so. Do not overcinch them. Keep them snug but don't tighten them so much that any of the cables deform. 4. Keep cables away from devices that can introduce EMI noise. Among others, these include: Copy machines, computer monitors, power supplies, UPS units, speakers, printers, AC power cables, electric heaters, fans, Fluorescent lights , telephones RF antennas or transmission lines, copiers, radio transmitters, TV sets XRay Machines, microwave ovens, unshielded transformers, refrigerator compressor motors, dishwashing machine motors, Electric garage door openers, elevator motors, electric ovens, dryers, washing machines, welding machines, and shop equipment. Cabling Rules (continued) Cabling Rules 5. Power cables and Ethernet twisted pair cables don't coexist well. Do not run Ethernet cables parallel to power cables. Yes, we know that this is a repeat of number 4 but it is worth repeating... DO NOT RUN ETHERNET CABLES PARALLEL TO POWER CABLES! 6. Do not stretch UTP cables when pulling cable. The maximum force on a cable should be 25 LBS or less. 7. Do not use metal staples or insulated metal U shaped cable clips to secure UTP cables. Use telephone wire hangers, preferably ones with plastic hangers for the wire. 8. Never, Never run UTP cable outside a building. It presents a very attractive lightning rod and will prove dangerous to you and your network's health! Finishing the job Finishing the job For portability and flexibility Install Wall plates with keystone jacks Use a central wiring distribution plan for all your wiring needs Wall Plates (aka, gang plates) Wall Plates (aka, gang plates) The outlet pieces on the top are inserted into the wall plates to create a finished look Using Keystone Jacks Using Keystone Jacks Keystone jacks are used in wall plates to offer a finished appearance. Proper termination ensures a good connection Lay the wire conductors into the Lay the wire conductors into the punch down slots Standard Wiring for Jack from Jack face view Terminating the connector Terminating the connector Some keystone jacks are self terminating and only require a cap to be put into position and pressed down Terminating the connector Terminating the connector For keystone jacks that do not self terminate, you can sometimes use a punchdown tool to seat the connections The punchdown tool cuts the excess wire The punchdown tool cuts the excess wire and seats the connection simultaneously Finishing the job Finishing the job The assembled keystone jack is then snapped into the back of the wall plate The wall plate can then be mounted into its protective gang box Structured Wiring Structured Wiring Structured Wiring means having wiring plan that conforms to a designated standard used by larger networks This will be covered in more detail in later classes Can also be useful in home networks that are more sophisticated Lesson Review Lesson Review When do you use a crossover cable When do you use a straight cable How would you test your cable What is a keystone jack used for What are some cabling practices that will avoid poor quality results ...
View Full Document
- Spring '09
- Networking, Crossover Cable