Cables and Connectors

Topic: Cables and Connectors Class: SSS Three

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Network Cables

Network cables are the physical pathways or mediums through which digital information (data) travels from one device to another in a computer network. They are essential for connecting computers, servers, and other network devices to allow communication.

Types of Network Cables

Network cables come in various types, each designed for specific purposes and environments:

1. Unshielded Twisted Pair (UTP) Cables
2. Shielded Twisted Pair (STP) Cables
3. Coaxial Cables
4. Fiber Optic Cables
5. Telephone Cables (often used for internet access via DSL)
6. *Note: While not a cable, Wireless (Wi-Fi) is another crucial medium for network communication today.*

Unshielded Twisted Pair (UTP) Cable

UTP (Unshielded Twisted Pair) cable is a very popular type of network cable. It consists of multiple pairs of copper wires, with each pair twisted around each other. This twisting helps to reduce electromagnetic interference from other pairs in the cable and from external sources.

Due to its relatively low cost and ease of installation, UTP cabling is widely used for Local Area Networks (LANs), such as connecting computers in offices or homes, and also for traditional telephone connections. While it may not offer as high bandwidth or as strong protection from interference as coaxial or fiber optic cables, it is a cost-effective and practical solution for many networking needs.

Shielded Twisted Pair (STP) Cables

STP (Shielded Twisted Pair) cable is similar to UTP but includes an extra protective shield (often foil or braid) wrapped around the twisted pairs. This shield provides additional protection against electromagnetic interference (EMI) and radio frequency interference (RFI), making it suitable for environments with high electrical noise.

However, the added shielding makes STP cables generally more expensive, thicker, and less flexible than UTP cables. They also require proper grounding for the shielding to be effective.

Coaxial Cable

A coaxial cable has a distinct structure: it features a single copper conductor at its very center. This central conductor is surrounded by a plastic insulating layer, which separates it from a braided metal shield. This metal shield acts as a barrier, helping to block any outside interference from sources like fluorescent lights, electric motors, or other computers, ensuring a clearer signal.

There are two main types of coaxial cabling:

1. Thin coaxial cables (Thinnet): More flexible and easier to work with, but with shorter maximum lengths.
2. Thick coaxial cables (Thicknet): Less flexible but can carry signals over longer distances.

Fiber Optic Cable

Fiber optic cable is a highly advanced type of network cable that transmits data using light signals, rather than electrical signals. It consists of a central glass or plastic core surrounded by several layers of protective materials. Because it uses light, fiber optic cable completely eliminates the problem of electrical interference, making it ideal for very fast data transmission over long distances.

Telephone Cable

Telephone cables are typically used for connecting traditional telephone systems, conveying low-voltage electrical signals to phones, modems, and fax machines. While not primarily designed for high-speed computer networks, they are commonly used in many homes and offices to provide internet access via DSL (Digital Subscriber Line) technology.

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Network Connectors

An electrical connector is a device used to join electrical circuits together, allowing electricity or data to flow between them. In networking, these connectors are used to attach cables to network devices.

Common types of network connectors include:

1. Registered Jacks (e.g., RJ45, RJ11)
2. Coaxial Connectors (e.g., BNC connector)
3. T-connectors

Registered Jacks (RJ)

The naming convention for Registered Jacks is RJ-xx, where "xx" is a two-digit number indicating the type of interface and its application area.

Examples of Registered Jack connectors:

• a. RJ45 Connector: This is a plastic connector that looks like a larger telephone-style connector. It has eight pins and is primarily used with UTP and STP network cables to connect devices like computers, routers, and switches in Ethernet networks. A slot on the connector ensures it can only be inserted one way.
• b. RJ11 Connector: The RJ11 is the most common phone jack in use today. It typically has four pins (though only two or four are usually wired) and is used to connect telephones, modems, and fax machines to telephone lines (POTS - Plain Old Telephone Service).

Coaxial Cable Connectors

The most common type of connector used with coaxial cable is the BNC (Bayonet Neill-Concelman) connector. This connector uses a twist-and-lock mechanism to secure the connection, making it reliable for connecting coaxial cables to devices in older network setups or for video equipment.

T-Connector

T-connectors are specifically designed for connecting three cables, typically in older coaxial Ethernet networks. They are shaped like the capital letter "T," allowing a single cable to split into two connections, often used to connect a single computer to a coaxial backbone cable.

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Computer Cables (General Purpose)

Beyond network-specific cables, computers use various other cables for power and connecting different peripheral devices:

1. Power Cable
2. Data Cable (Internal)
3. Printer Cable
4. Monitor Cable
5. Serial Cable
6. Universal Serial Bus (USB) Cable

Power Cable

A power cable (or mains cable) is a cord that temporarily connects an electrical appliance, such as a computer, monitor, or printer, to an electrical power source, usually a wall socket or an extension cord. It supplies the necessary electricity for the device to operate.

Data Cable (Internal/External)

Data cables are used to transmit information. Internally, they connect components within a computer (like a hard drive to the motherboard). Externally, they connect peripheral devices (like external hard drives or cameras) to the computer's system bus. Examples include SATA cables (internal) or specialized USB data cables (external).

Printer Cable

A printer cable is specifically designed to connect a printer to a computer. Traditionally, this was a parallel cable connecting to a parallel port on a PC. Today, most printers connect via USB or wirelessly. A parallel port is a type of interface on computers primarily used for connecting older peripheral devices like printers.

Monitor Cable

A monitor cable (like a VGA, DVI, HDMI, or DisplayPort cable) is used to transmit video signals from a computer's graphics card to a display device (monitor or projector), allowing images to be shown on the screen.

Serial Cable

A serial cable is a cable used to transfer information between two devices using a serial communication protocol, meaning data is sent one bit at a time, sequentially. They were commonly used for older modems, mice, and some network devices before USB became widespread.

Universal Serial Bus (USB) Cable

A Universal Serial Bus (USB) cable is a versatile cable widely used for connecting a vast array of peripheral devices (like keyboards, mice, printers, external hard drives, smartphones, etc.) to a computer. USB is popular because it can provide both power and data transfer over a single cable, and it's a universal standard.

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Computer Connectors (Gender)

When talking about electrical and computer connectors, we often classify them by "gender":

• Male Connectors: A male connector has one or more protrusions (like pins or prongs) that are designed to fit into a corresponding receptacle. Good examples include a standard electrical power plug or the end of a USB-A cable that plugs into your computer.
• Female Connectors: A female connector is a receptacle or socket that has holes or slots designed to receive the pins or prongs of a male connector. Virtually all the ports on a computer (like USB ports, Ethernet ports, and monitor ports) are female connectors.

In simple terms: the male connector has "pins" that stick out, while the female connector has "holes" or "receptacle contacts" for the pins to go into.

An example of a commonly encountered connector type is the RCA (Radio Corporation of America) connector, which is an electrical connector used to carry audio/video (A/V) signals, often seen on older TVs or sound systems.