Cable assembly is a professional job. Improperly made cables may create network outages, and lost business. Unless one is well experienced and proper tools, the work be better outsourced.
It is often recommended to lay the fiber for back bone, since it is immune to EMI and also can carry higher bandwidths.
Shielded Twisted Pair (STP): STP cables reduce electrical noise and electromagnetic radiation. In other words, they help to keep the signal steady, and reduce interference with other devices. Given below is a diagram showing a typical shielded twisted pair cable
Unshielded Twisted Pair (UTP): UTP cables do not have shielding to reduce interference. They are designed to cancel electromagnetic interference with the way the pairs are twisted inside the cable. Unshielded twisted cables are most widely used for office LANs, though recently wireless LANs are more widely used. Unshielded cables are lightweight, thin and flexible. They are also versatile and inexpensive. A typical UTP cable cross section is shown in the figure below:
The twisting of the pairs in typical Ethernet cabling provides some resistance to EMI/RFI, enough for use in the vast majority of applications. However, highly static prone areas like generator rooms or high voltage equipment rooms may need shielding of cables.
One dis-advantage of shielding is that you need to ground the connectors properly on the terminating ends of the cable, else static may build on the outer sheath of the cable and interfere with the signals, thus becoming worse than having no shielding at all.
1000BASE-T: 1000BASE-T, also known as IEEE 802.3ab is a standard for gigabit Ethernet over copper wiring. It requires, at least Category 5 cable, but Category 5e ( "Category 5 enhanced") or Category 6 cable may also be used and are often recommended. 1000BASE-T requires all four pairs to be present and is far less tolerant of poorly installed wiring 10BaseT/100BaseT/1000BaseT use RJ-45 connector.
Different types of cabling standard
Ethernet cables are grouped into sequentially numbered categories ("cat") based on different specifications; sometimes the category is updated with further clarification or testing standards (e.g. 5e, 6a). These categories are how we can easily know what type of cable we need for a specific application.
| CAT3 | CAT5 | CAT5e | CAT6 | CAT6e | CAT7 | |
|---|---|---|---|---|---|---|
| Speed | 16 Mbps | 100 Mbps | 1000 Mbps | 10/100/1000Mbps and 10 Gbps | 10/100/1000 Mbps and 10 Gbps |
10/100/1000 Mbps and 10 Gbps |
| Limitation | Ineffective for Higher - speed networks often found in older 10 BaseT networks | Range of 100 meters | Range of 100 meters | Range of 100 meters | Range of 100 meters | Range over 100 meters |
Important points to remember
CAT6 is rated for gigabit Ethernet while CAT6e is thicker and rated for 10 gig Ethernet. Typically CAT5e is sufficient and can also handle gig Ethernet, but noise margin will be less.
Connectors
An RJ-45 connector has 8 connection pins and can accommodate 4 pairs of wires.
The connector shown in the exhibit is RJ-45 connector. RJ-45 connector is the most commonly used connector in 10BaseT, and 100BaseT networks. RJ-11 connectors are commonly available either with 4-wire or 6-wire, whereas RJ-45 has 8 wires (4-pairs). An RJ-45 connector has 8 connection pins and can accommodate 4 pairs of wires. Typically, a UTP cable with RJ-45 connectors is used to connect the NIC card on the home computer with the DSL broadband modem.
RJ-48C: RJ-48C connectors are 8-pin jacks (think RJ-45) used with T1 lines. Pins 1, 2, 4, and 5 are used for data (1 and 2 for receiving; 4 and 5 for transmitting), and pins 7 and 8 are used for cable shield integrity. Pins 3 and 6 are not used. A common connection type used to connect to a CSU/DSU is an RJ-48C.
RJ-11 (Registered Jack) connectors are small plastic connectors used on telephone cables.
The connector shown in the exhibit is a 4-wire RJ-11 connector. RJ-11 connectors are also available in 6-wire.
Two frequently used Firewire connectors are 4-pin connector, and 6-pin connector. A 4-pin connector does not carry power through the connector, whereas a 6-pin connector carries the dc-power required for operating the connected device.
RS-232: RS-232 (Recommended Standard) is a TIA/EIA standard for serial transmission between computers and peripheral devices.
Fiber Connectors: The below figure shows the different fiber connector types .
1. ST connectors: These connectors are the most common type of commercial fiber optic connector. These connectors utilize an exposed plastic tube housing the optical fiber. This requires a connection to a matching cable on the other side, incorporating a connector that mates to the other. These combine in a spring-loaded twist, reminiscent of BNC connectors, and are noted for their reliability. ST connector is very popular in communication applications, such as LANs and CCTV systems.
2. SC-Connector: SC is short for Subscriber Connect is one of the most frequently used connectors. Used in fiber-optic networking, it has caps to prevent laser light reaching eyes. The connector usually in pairs (transmit and receive), often clipped together. connectors have the ferrule that houses the fiber mostly concealed. Probably the most similar commercial equivalent of To slink, SC connectors does not require a mating cable on the other side. Instead, these snap-on connectors simply push into their jacks with a click. SC connectors use a push-pull design and can be used for simplex or multiplex applications
3. FC connector: It is similar to ST connectors, these fiber optic connector's screws into their mating jacks. Additionally, the tube surrounding the optical fiber is typically shrouded in ceramic or metal, as opposed to being fully exposed. The inner ring of the connector is keyed to ensure positive mating to its corresponding jack. FC connectors are primarily used with single mode fibers and used in telephone, instruments, and high-speed communication links. The style is similar to that of an ST connector, but it uses a threaded connection which makes it better suited for high vibration environments.
4. LC cables: latch and release into their jacks in a manner similar to Ethernet connectors. Smaller in form than SC connectors, their durability is not compromised, nor is cost increased. Instead of snapping or thermo forming the connector to the cable, it is glued. This makes it a popular connector for field use. LC connectors are used in private and public networks, and are gaining in popularity due to their small form factor (SFF) optical transmitter/receiver assemblie
LC connector is a miniaturized version of the fiber-optic SC connector. It looks just like the SC, but is half the size with a 1.25 mm ferrule instead of 2.5 mm. 1000BASE-FX should use SC, ST, LC, MTRJ or MIC connectors with SC being the preferred option. MT-RJ Connector, LC Connector are small form factor connectors.
Usually, cable modems use F-type female connector to connect to the broadband provider.
ST (Short for Straight Tip) connectors, and SC (short for Subscriber Connect) connectors are typically large connectors. MT-RJ, and LC (short for Local Connector) have small form factor, and allow higher port density. These connectors (MT-RJ and LC) allow higher number of fiber optic connections in a smaller area, and hence desirable when there are a large number of fiber optic terminations to be made.
SFP (Small Form-factor Pluggable): SFP is a small transceiver that plugs into the SFP port of a network switch and connects to Fibre Channel and Gigabit Ethernet (GbE) optical fiber cables at the other end. Superseding the GBIC transceiver, SFP modules are also called "mini-GBIC" due to their smaller size. By choosing the appropriate SFP module, the same electrical port on the switch can connect to fibers of different types (multi-mode or single-mode) and different wavelengths. If the fiber is upgraded, the SFP module is replaced.
The SFP converts the serial electrical signals to serial optical signals and vice versa. SFP modules are hot swappable and contain ID and system information for the switch.
Rollover cable (also known as Cisco console cable): It is a type of null-modem cable that is often used to connect a computer terminal to a router's console port. This is typically a flat blue color that distinguishes itself from other types of network cabling. It is most commonly used to connect a computer terminal to a router's console port.
Straight through and Cross over cables: Ethernet network cables are primarily straight or crossover. This Ethernet network cable is made of 4 pairs of wires that consists twisted pair conductors (totally 8 conducting wires) that used for data transmission. Both end of cable is terminated with RJ45 connector. The wires in straight through cable are connected to the RJ-45 in the same pattern on either end of the cable, where as in Cross over cable, transmit and receive pin wires are interchanged. The straight through cable is used for connecting a computer to a hub or switch. The Cross over cable is used for connecting a switch to another switch or a hub.
Note: Sometimes, switches will have an "uplink" port. If you are connecting to an "uplink" port of a switch from the regular port of another switch/hub, you need to use straight-through cable. If you are connecting to a regular RJ-45 port of a switch from another switch's regular RJ-45 port, then you need to use Cross-over cable. Similarly, if you want to directly connect two computers, then you need to use Cross-over cable. This is because, the transmit at one end becomes receive port at the other end.
Patch cable is a generic term used, and may represent any cable that connects two networking devices. They are typically CAT5 / CAT5e/CAT6 Ethernet cables linking a computer to a nearby network hub, switch or router.
