Computer Networking Cables - Types and Usage FAQ

Some unanswered questions and there answers..enjoy.... 

Q. What is an unshielded network cable?

A. Unshielded Twisted Pair cables are widely used with the Ethernet networks. The twisted wire pairs in the cable, as suggested by the name, are not shielded. Eight individual copper wires (22 or 24 gauge) are twisted to make four pairs that restrict the signal corruption due to electromagnetic interference. UTP cables must adhere to the specifications regulating the number of twists that are permitted in defined length. A relatively smaller diameter of this cable is beneficial during installation. The speed and throughput of this cable is 10 to 1000 Mbps and is the most cost effective networking cable. This cable is extremely popular because it can be effectively used with most of the major networking infrastructure.

Q. What is a shielded network cable?

A. In the Shielded Twisted Pair cables, a metallic foil is used for wrapping each pair of copper wire which are then blanketed altogether in a metallic braid. STP not only reduces the outside disturbance like the EMI and RFI radiations but also the electrical noises in the cables like crosstalk and pair-to-pair to coupling. It is generally installed with the STP data connector but can also use RJ connector base. Unlike UTP, number of twisted pairs in this cable are only two and are comparatively more difficult to install. When installing, you must ensure that the metallic shield on both the ends is properly grounded.

Q. When do I need a shielded cable and which type do I need?

A. The main use of shielded cable is to strengthen the signal transmission via the cable and protect it from disturbances like crosstalk, Electromagnetic Interference (EMI) and Radio Frequency Interference. This interference usually occurs when there are any kinks or crimps from the neighbouring structures. These cause the transmission of data to slowdown. Common sources causing the disturbances are large motors and generators, radio towers and high-voltage lighting fixtures.

Q. What is a crossover cable?

A. A crossover cable, also known as cross wired cable, is a network cable that is used for the connection of two network devices without the need of any hub or switch. These cables are terminated distinctively on one of its ends with pairs switched green and orange. This cable also enables you to directly access the hardware on the same network.

Q. What is a solid cable?

A. Within the jacket of a solid cable, also known as one strand cable, there's only one solid piece of copper wire. Solid cables give mechanical ruggedness and because it's a single conductor, this cable can be used for structured wiring inside a building. In an insulation displacement connector, it's easier to place solid cables.

Q. What is a stranded cable?

A. A stranded cable consists of numerous thin copper wires bundled within a jacket. Each one of these thin strands within the cable can be bent and flexed conveniently. Owing to their flexibility, these cables are mainly to make patch cables that can easily be plugged, unplugged and installed. Even if the stranded cables are twisted frequently, these neither corrupt nor affect the signal strength.

Q. Which type do I need, solid or stranded?

A. Though both the cables, solid and stranded have the same signal strengths, stranded cables are considered better for short lengths due to their flexibility. On the other hand, solid cables are much better for long cable runs.

Q. What is the maximum length?

A. The maximum recommended length for networking cables is 330ft (100m) which is based upon the solid cable as it's the preferred choice for maximum length. Always make it a point to use repeaters at the length of patch cables. The distance between two of the patch cords should be 30ft (8m). another thing you have to pay heed to is the bending of the cables. Since these are rated with the least bending capacities, the signals are slowed down in case of a severe bending.

Q. What is RJ45?

A. Just like the lines on the road control the traffic, connectors, at the end of cables, line up the wires in physical locations inside themselves. In network installation, RJ45 connectors are used specifically for connecting the Ethernet devices.

NETWORK CABLE TYPES

Network cabling tutorial: cable type, connector, installation guide, tips

Cable is the medium through which information usually moves from one network device to another. There are several types of cable which are commonly used with LANs. In some cases, a network will utilize only one type of cable, other networks will use a variety of cable types. The type of cable chosen for a network is related to the network's topology, protocol, and size. Understanding the characteristics of different types of cable and how they are related to other aspects of a network is important for the development of a successful network.

Cable Standard

10BASE-T Cable Standard

10Base-T is one of the Ethernet standards for cabling in a network environment. 10BaseT uses a twisted pair cable with a maximum length of 100 meters. Standard 10BaseT operates at 10 Mbps. It is commonly used in a star topology.

10BASE-FL Cable Standard

10BaseFL is a fiber optic cable standard designed to run at 10 Mbps. It is similar to 10Base-T, though the media type is fiber. For use up to 2000 meters.

100BASE-TX Cable Standard

100 Mbps Fast Ethernet over category 5 twisted pair cable. Maximum cable length of 100 meters.

100BASE-FX Cable Standard

100 Mbps Fast Ethernet standard over fiber cable. Can transmit data up to 2000 meters.

1000BASE-T Cable Standard

Gigabit ethernet over twisted pair copper wires. Transmit up to 1000 Mbps. 100 meter maximum cable length. Cat5 or better required (Cat6 cabling recommended).

1000BASE-CX Cable Standard

Gigabit ethernet over a special copper twinax cable. Up to 25 meters in length. Typically used in a wiring closet or data center as a short jumper cable.

1000BASE-SX Cable Standard

Gigabit ethernet using a short-wavelength laser device over multimode fiber optic cable. 50 um core (max 300 meters) or 62.5 um core (max 500 meters). 1000Mbps maximum transfer speed.

1000BASE-LX Cable Standard

Gigabit ethernet using long-wavelength laser transmitters over fiber optic cable. Up to 3,000 meters. Uses singlemode fiber and requires SC connectors for terminating the cable.

10 GBASE-SR Cable Standard

802.3ae standard. 33 meters for 62.5um fiber optic cable, 300 meters for 50um cables. 10 Gbps (Gigabit per second) transfer rate.

10 GBASE-LR Standard

10 Gbps transfer rate. 10 kilometers maximum distance. Fiber optic cable.

10 GBASE-ER Standard

10 Gbps transfer rate. 40 kilometers maximum cable length. Fiber optic cable.

Types of cables

Category 3 cable is what you commonly referred to as "telephone cable." It is a twisted pair cable with a throughput of about 10 Mbps. It has been used in the past for 10Mbps Ethernet and 4Mbps Token Ring networks. Currently not recommended for data networking installations.

Category 5, CAT5, cable is the most data networking cable for ethernet networks. Cat5 has a maximum throughput of 100Mbps. It is a four-pair cable, unshielded twisted pair.

Category 5e, or CAT5 Enhanced, cable is used to achieve 1000Mbps (Gigabit ethernet) in installations. It does have some noise susceptibility problems, but is frequently used in networking installations.

Category 6 cable is the new standard allowing for up to 2.4 Gbps in theory. Each wire is wrapped in foil insulation in a CAT6 cable. Not as popular as CAT5 (primarily due to cost) but for some applications like PoE (Power over Ethernet), CAT6 is a requirement. Cisco IP phones use PoE to deliver power to the telephone. If you implement CAT6, you should make sure your entire infrastructure is CAT6.

Unshield Twisted Pair cables is the cable used to implement 10BaseT and 100BaseT networks. Wires are twisted around each other though each individual wire is not insulated. Commonly used in CAT5 cabling.

Shielded Twisted Pair cables is used in CAT6 cables. Each wire is shielded with a metallic shield to reduce electromagnetic interference. The outer shield may be in the form of a thin metallic mesh in the case of ScTP (Screened Twisted Pair) or a very thin metallic foil in the case of FTP (Foil Twisted Pair).

Coaxial Cables are what you commonly see in a video installation. It is also used in networking. The cabling has a central solid wire core, insulation, and is surrounded by a braided wire conductor sheath. Coaxial cable is relatively resistant to interference. In networking, Coaxial cables use BNC connectors.

Single Mode Fiber (SMF) optical cables are used for long distance and high speed transmissions. This cable is often used in long distance telephone lines. The core diameter is typically less than 10 microns.

Multimode Fiber optical cables are typically used for short distances. It hs a larger core than SFM, typically 50 to 100 microns in size. It can carry about 100 Mbps in a typical short area. Typically used in installations up to 2000 meters in length.

Cable connectors

RJ-11 Connector is commonly used as a telephone connection, the RJ11 connector is smaller than its older brother, the RJ45. Your telephone, answering machine, and modem all have RJ11 connectors.

RJ-45 Connector is your common 10BaseT cable connector for networking. Your computer or laptop has a RJ-45 connection if you have a network card.

F-Type Connector is a threaded connection most often used to link coax cables to home electronics. Also used in the coax network. Your cable box at home? F-Type connector.

ST (Straight Tip) Connector is a fiber optic cable connector. Originally developed by AT&T.

SC (Standard) Connectoris a square shaped push/pull snap-in fiber optic connector.

IEEE 1394 (Firewire) Connector is created by Apple as a high speed cable connection, Firewire is becoming increasingly standard as it is used for fast external drives and digital video editing. Can transmit data up to 400 Mbps.

Fiber Local Connector is the fiber optic cable connector.

MT-RJ Connector is the fiber optic cable connector.

USB Connector is probably the most familiar one to you. Often used in computing for a variety of peripherals including mice, scanners, cameras, etc. USB can transmit up to 12 Mbps and can connect up to 127 peripherals on one port. USB 2.0 can transfer at up to 480 Mbps.

Cable installation guide

When installing cable, the following a few simple rules need to be followed:

1. Always use more cable than you need and leave plenty of slack.

2. Test every part of a network as you install it. Even if it is brand new, it may have problems that will be difficult to isolate later.

3. Stay at least 3 feet away from fluorescent light boxes and other sources of electrical interference.

4. If running cable across the floor, cover the cable with cable protectors.

5. Label both ends of each cable.

6. Use cable ties (not tape) to keep cables in the same location together.

Miscellaneous Cable Information

1. Shielded twisted pair (STP) differs from UTP in that it has a foil jacket that helps prevent crosstalk. Crosstalk is signal overflow from an adjacent wire.

2. The 5-4-3 rule: this rule states that a 10base2 network can have 5 cable segments connected with 4 repeaters, but only 3 of these segments can be occupied by computers. There is also a maximum of 30 computers per segment.

3. Plenum grade cabling is required if the cabling will be run between the ceiling and the next floor (this is called the plenum). Plenum grade cabling is resistant to fire and does not emit poisonous gasses when burned.

4. Fiber Optic cabling has an built in security as you can't intercept data as you can with other cable mediums.