220-1201 Hardware Study Guide for the CompTIA A+ Core Series Exam

Cables and Connectors

A cable is a physical medium used to create a connection between devices in a network for the transmission of data between the connected devices. A connector is a physical medium that terminates a cable to provide a method of connection between the port designed to receive the connector and the attached cable. Cables and connectors, by themselves, are passive mediums and require connection to an active device for functionality. You must be able to describe the different cable types and their characteristics and uses, including connector types, features, and purposes.

Network Cables

Network cables are used to connect devices such as computers to networking equipment. There are three primary types of network cable: coaxial, twisted-pair, and fiber. A cable is the medium through which data is transferred from one device to another.

Copper

Copper is the most common medium used in both coaxial and twisted-pair cables. Copper wire is used as the conductor for transmitting data using electrical pulses.

Categories

Categories are used to describe performance ratings of twisted-pair cables. Commonly referred to as Cat cables, Category 1 through 8 exist. All Cat cables from 2 to 8 are composed of four pairs of twisted pairs, totaling eight individual wires in one cable sheath.

T568A— Twisted-pair wires are color coded for proper referencing. T568A and T568B are the two standards used for RJ45 wiring connectors. The T568A standard is green/white, green, orange/white, blue, blue/white, orange, brown/white, and brown.

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T568B— The T568B standard is orange/white, orange, green/white, blue, blue/white, green, brown/white, and brown.

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COAXIAL

A coaxial cable is a single copper-cored cable contained in an inner insulation layer. This inner layer is further contained in a wire mesh conductor. The entire cable is then further protected in an outer insulation layer. Coaxial cables are not as commonly used in modern networks, but some usage may still be seen with cable and satellite devices. Coaxial cables are specified by the Radio Guide (RG) system. For the purpose of the test, you need to be familiar with RG-6, which is made of a solid copper core used with satellite/cable modems, and RG-59, which is made of a solid copper core and used for cable television.

Shielded Twisted-Pair (STP)

A twisted copper pair is a twisted-pair cable made of copper. The cable consists of pairs of individual wires twisted into pairs, which are then twisted together. The cable is contained within an insulated jacket. Ethernet cables are twisted pairs. An STP cable is made of two to four pairs of twisted wires. Each pair is contained in a layer of braided foil sheathing before being twisted with the other pairs in the cable. This reduces electrical interference. STP is used in Cat 7 and Cat 8 cables.

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direct burial—Direct burial is the practice of burying cables underground. Direct burial cables should be STP cables with an extra waterproof sheathing. It is recommended that direct burial be between six and eight inches underground in a protective PVC pipe and placed away from any other lines that contain electrical current.

Unshielded Twisted-Pair (UTP)

A UTP cable is made of two to four pairs of twisted wires. The pairs of wires in UTP cables are twisted in direct contact with one another. Each wire in twisted pairs is contained within an insulating layer, preventing copper from directly touching copper.

Plenum-Rated

Plenum is a Teflon-type covering used to cover all types of network cables. Plenum is used in plenum-rated cables that may be exposed to extreme heat or have the possibility of releasing gases into a ventilation system, such as in ceilings.

Optical

Optical is a transmission method that depends on light pulses for data transfer. Fiber refers to the small strings of flexible glass that are used for optical data transmission. Known as fiber-optic cables, a fiber is surrounded by a rubberized coating and provides transmission speeds from 100 Mbps to 10 Gbps over a maximum distance of several miles. Fiber is immune to both electrical interference and wiretapping. There are two basic types of fiber: single-mode and multimode.

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Single-Mode

Single-mode fiber has a smaller core and carries only one light path, typically sourced by a laser. Single-mode has a higher bandwidth and much longer transmission distance than multimode.

Multimode

Multimode fiber has a larger core and carries multiple light paths, which can be sourced by LEDs or vertical-cavity surface-emitting lasers (VCSELs), which are cheaper to produce and have a wider beam. Multimode fibers have limited bandwidth compared to single-mode fiber and a shorter transmission distance.

Peripheral Cables

Peripheral cables attach peripheral devices to a computing device. They are used to attach things like printers, keyboards, monitors, and USB devices.

Universal Serial Bus (USB) 2.0

The USB 2.0 standard transmits data via a half-duplex system, which only allows for data to be transmitted one way at a time, has a max speed of 480 Mbps, and is also referred to as Hi-Speed USB. USB cables transmit data through serial communications.

Universal Serial Bus (USB) 3.0

The USB 3.0 standard transmits data via full-duplex, which allows data to be sent and received simultaneously, has a max speed of 5 Gbps, and is referred to as SuperSpeed.

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Serial

A serial cable, also known as an RS-232 cable, is built for serial communications with a corresponding serial connector on the end. Data is sent bit by bit sequentially over a single full-duplex cable. The most common serial connection type is a D-subminiature cable, such as a DB9 connector, which has nine pins, or a DB25, which has 25 pins.

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Thunderbolt

Thunderbolt is a combination of PCI Express 2.0 x4 and DisplayPort 1.x technology. Thunderbolt cables transmit data through full-duplex serial communications. Thunderbolt was designed primarily for video transmission but can be used by other peripheral devices as well. There are four Thunderbolt standards labeled 1 to 4, with Thunderbolt 1 and 2 terminating in Mini DisplayPort connectors and Thunderbolt 3 and 4 terminating in USB-C connectors.

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Video Cables

A video cable is designed to transmit data to visual display units.

High-Definition Multimedia Interface (HDMI)

The HDMI cable is capable of handling higher motion-picture frame rates and digital audio on a single cable. The most common connector type for an HDMI cable is the Standard A HDMI cable, which has 19 pins.

DisplayPort

DisplayPort was developed to use less power than previous video cables. DisplayPort is backward compatible with VGA and DVI connectors. DisplayPort is also capable of transmitting both video and audio signals. A standard DP cable has two hooks on it to lock the cable into place.

Digital Visual Interface (DVI)

The DVI cable was developed to address the shortcomings of analog video transmission. DVI cables are capable of transmitting digital video signals to display units. The three DVI connector standards are DVI-A with 17 pins for analog connection only, DVI-D with 19 pins for single-link and 25 pins for dual-link for digital connection only, and DVI-I with 29 pins for both analog and digital signals. DVI cables are typically white.

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Video Graphics Array (VGA)

The VGA cable is the oldest video standard still in use today. A VGA cable is strictly analog and is typically blue in color with 15 pins.

USB-C

Not all USB-C cables are capable of transmitting video. To be video compatible, the USB-C port and the USB-C cable must support DisplayPort Alternate Mode (DP Alt-Mode) or the Thunderbolt protocol, which is indicated by the DP Alt-Mode or Thunderbolt symbol.

Hard Drive Cables

Hard drive cables/connectors connect internal components to the motherboard. Hard drive connections, known as drive interfaces, can be either on-board or off-board. Their attachment standard is based on the hard drive’s requirements and consists of circuitry and a header, or port.

Serial Advanced Technology Attachment (SATA)

SATA is the most common type of drive interface. A standard SATA cable is internal and flat with a terminating connector that can only fit into the motherboard connection port in one way. A SATA data cable has seven pins, while a SATA power cable has 15 pins. SATA revisions 1.0, 2.0, 3.0, and 3.2 support speeds of 1.5 Gbps, 3 Gbps, 6 Gbps, and 16 Gbps, respectively.

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External SATA (eSATA)

The eSATA cable, as the name suggests, is external to the housing. Standard eSATA cables are for data transmission only and do not provide power. An eSATA that provides power is called Power over eSATA, eSATA+, eSATAp, or eSATA/USB.

Adapters

An adapter is a device that converts one type of connection or cable technology to another, such as a DVI-to-VGA, DVI-to-HDMI, or USB-to-Ethernet.

Connector Types

Connectors are installed at the terminating points of cables to provide a connection to compatible components and peripherals. The connector type used depends on the type of cable and the desired receptacle compatibility.

registered jack 11 (RJ11)—An RJ11 is a telecommunication network interface standard for connecting voice and data equipment to a service provider or carrier. RJ11 is used with twisted-pair cables to connect four to six wires to traditional telephone lines or modems.

RJ45—RJ45 is used with twisted-pair cables for eight-wire connections. A twisted-pair cable with RJ45 connectors is commonly called an ethernet cable.

F-type—An F-type connector (or just F connector) is used with coaxial cables for cable and satellite data connections.

straight tip (ST)—An ST connector is a bayonet-style connector used with fiber-optic cables.

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subscriber connector (SC)—An SC is a push/pull-style connector used with fiber-optic cables.

lucent connector (LC)—An LC is a push/pull-style connector used with fiber-optic cables that is half the size of an SC, making it more suitable for office and data center usage.

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punchdown block—A punchdown block is an electrical connection device that allows for multiple copper wires to be “punched down” or inserted into a slot, providing insulation as well as electrical connection to attached wires.

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Micro USB—A Micro USB connector is the smallest USB connector type, contains five pins, and is direction dependent.

Mini USB—A Mini USB is the second smallest USB connector type, contains five pins, and is direction dependent.

USB-C—USB-C is the most recent USB connector type. It contains 24 pins in an oval shape, allowing for reversible connection.

Molex—Molex is an older two-piece pin-and-socket interconnection type used for drive connections. The most common Molex connector is the four-pin connector used for peripheral power.

Lightning—A Lightning port is an eight-pin Apple proprietary connector type that has reversible orientation.

DB9—The DB9 is a trapezoid-shaped nine-pin connector arranged in two rows of four and five pins. It is used for serial connections to network device consoles or management ports.

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Note: The term “DB9” is commonly used but is technically incorrect; the proper name is “DE9,” referring to the size of the connector’s shell and the number of pins (nine pins in an E-size shell), with DE indicating a smaller shell size than DB. However, given that this misconception has been prevalent for so long in the industry, the CompTIA exam uses the term DB9.