CompTIA A+ Section 2: Cable Types

Bit (b)

Refers to a binary digit; A single bit can store only one of two values: 1 or 0. Used to measure data transfers.

Nibble

4 bits that are combined together.

Byte (B)

Contains 8 bits. Used to measure data storage.

Kilobits (Kb)

1000 bits.

Megabits (Mb)

1 million bits.

Gigabits (Gb)

1 billion bits.

Terabits (Tb)

1 trillion bits.

Video Cables

Designed to transmit data to visual display units.

USB

Universal Serial Bus

USB Type A (USB-A)

The most common and widely recognized rectangular USB port, found on devices like computers, laptops, TVs, and gaming consoles, used for connecting peripherals and transferring data and power. Can only be inserted in one direction.

USB Type B (USB-B)

A square-shaped connector commonly found on peripherals like printers and scanners. Used for connecting peripherals and transferring data and power. There are three types of USB Type B; Type B Standard, Type B Mini, and Type B Micro. Can only be inserted in one direction.

USB Type-C (USB-C)

A small, reversible connector commonly found on smartphones, laptops, and peripherals designed to transmit data, power, and video.

Serial Cables

They are used to transfer data. Used on things like routers, switches older mice, keyboards, and external modems. Data transmission over serial cables is considered to be very slow because data is sent one bit at a time and its measured bits per second, with a maximum speed of 115 Kilobits per second.

Powered Device Port (PD)

A port, typically a USB port, that can supply power to a device, even when the computer is off or in a low-power state, allowing for charging or powering of devices like phones or external hard drives.

High-Definition Multimedia Interface (HDMI)

A digital interface that transmits high-definition video and audio signals over a single cable, replacing older analog standards like VGA and DVI. Used on video game counsels, tv's, Blue ray players, computer, and laptops. There are three different connector types; Type A- regular full size connector, type C- mini connector, and Type B- micro connector.

Display Port (DP)

A digital audio/video interface standard developed by the Video Electronics Standards Association (VESA) primarily used to connect a computer to a monitor, supporting high resolutions, refresh rates, and audio transmission, and also used in some consumer electronics devices. There are two sizes, Full size display port- DP and Mini display port MiniDP or mPD. Can only be inserted in one direction.

Digital Visual Interface (DVI)

Legacy video interface that supports digital only or digital and analog signaling. Used to transmit video signals. There are three different types; DVI-A only supports analog signals, DVI-D only supports digital signals, and DVI-I is integrated which means it can support both analog and digital signals.

Video Graphics Array (VGA)

A 15-pin D-subminiature connector used to transmit analog video signals from a computer or video source to a display device like a monitor or projector. It is considered to be a Legacy technology.

Thunderbolt

A high-speed data transfer, video output, and power delivery cable, typically using a USB-C connector, that supports the Thunderbolt protocol for faster and more versatile connectivity than standard USB-C. Not all Thunderbolt can be used on USB- C but all USB-C will work on Thunderbolt.

Storage Cables

Cables used to connect storage devices to a computer.

Lightning cable

A proprietary connector and cable used by Apple to charge and sync devices like iPhones, iPads, and iPods, offering data transfer and power capabilities. It is Reversable.

Serial Advanced Technology Attachment (SATA)

The standard method of connecting a storage device to a motherboard inside a desktop computer. They have two types of cable; SATA 7-pin Data Cable- transfers data only and SATA 15-pin Power Connector- Provides power.

external SATA (eSATA)

The same type of as SATA but is used outside of case.

Small Computer Systems Interface (SCSI)

A legacy parallel bus connector that allows multiple devices to be Daisy chained together. There are two different types; Narrow SCSI- supported up to 7 devices and Wide SCSI- supported up to 15 devices.

Single Connector Attachment (SCA)

A type of 80-pin connector used in Parallel SCSI systems, designed to carry both data, power, and configuration signals through a single connector, simplifying internal cabling and installation.

Serial Attached SCSI (SAS)

High performance data transfer technology used mainly in enterprise environments for connecting storage devices to servers and work stations.