1.08 Explain basic cable types and their connectors, features and purposes

Introduction 

Connectors and cable types in a PC are like different keys that fit into specific locks. Just as each key is designed to fit only one particular lock to open a door, each connector and cable type is designed to fit only one type of port on a device. These connectors and cables allow different parts of the computer, like the monitor, keyboard, or hard drive, to connect and communicate properly. Without the right connectors and cables, the different components of a PC wouldn't be able to "unlock" their full potential, making it impossible for the computer to function correctly. That's why it's essential to know the different types and how they fit together. 

 

Understanding Peripheral Connections: I/O Ports, Connectors, and Data Transfer Essentials

Peripheral devices connect to a PC through input/output (I/O) ports using specific connectors and cables, which enable data transfer and communication between the computer and external devices. 

  • I/O Ports: Ports are located at the front or rear of the PC case and allow connections to devices like monitors, printers, and external drives. They can be built into the motherboard or added via an expansion card. 

  • Interfaces, Ports, and Connectors: Each port corresponds to a bus interface, which facilitates data transfer between the PC and the device. Connectors on cables match the port's shape or form factor, using keying or reversible designs to ensure correct attachment. 

  • Connector Types: Common connectors include USB, HDMI, DisplayPort, and Ethernet, each designed for specific device types or functions. These connectors ensure that data is transferred efficiently and securely. 

  • Binary Data Storage and Transfer Units: Data in computers is processed as binary digits, or bits (b), with storage often measured in bytes (B), where one byte equals eight bits. 

  • Transfer Rates: Data transfer rates for peripheral connections are measured in units per second. For example, USB 2.0 transfers data at up to 480 Mbps (megabits per second), USB 3.0 at up to 5 Gbps (gigabits per second), and USB 3.1 at up to 10 Gbps. Higher-speed interfaces like Thunderbolt 3 can achieve up to 40 Gbps, making them ideal for high-performance devices. These rates are essential for comparing the efficiency of different interfaces and choosing the right connection for a specific task. 

Storage Drive Cables 

SATA cables are used to connect internal storage devices to a motherboard, providing data transfer capabilities within a desktop PC setup. 

  

  • SATA Interface: Serial Advanced Technology Attachment (SATA) is the standard interface for connecting internal storage drives like hard drives and SSDs. SATA uses 7-pin data cables up to 1 meter (39 inches) in length, with each port on the host adapter supporting a single device.  

  • Data and Power Connectors: The 7-pin SATA data cable does not supply power. A separate 15-pin SATA power connector provides the necessary power from the PC's power supply. The power connector includes wires for 3.3V (orange), 5V (red), and 12V (yellow) DC. 

  • SATA Revisions: The original SATA standard supported data transfer speeds up to 150 MBps, with subsequent revisions increasing speeds to 300 MBps (SATA revision 2) and 600 MBps (SATA revision 3). 

7-pin SATA data cable

Molex Power Connectors: Legacy storage devices might use a Molex power connector instead of SATA. Molex connectors, made of white or clear plastic with 4 pins, are color-coded to indicate voltage levels: red (5V DC), yellow (12V DC), and black (ground). Some devices may support both SATA and Molex power options.  

15-pin SATA power connector

Molex connector

External SATA (eSATA): eSATA is an extension of the SATA standard for connecting external drives, supporting cable lengths up to 2 meters (78 inches). Unlike internal SATA cables, eSATA cables are designed specifically for external connections. Some systems use eSATAp, a powered version that combines eSATA and USB compatibility, though USB is more commonly used for external drives.

Universal Serial Bus (USB) 

USB (Universal Serial Bus) is the standard for connecting various peripheral devices to a computer, offering different versions with specific data transfer rates and connector types. 

  • USB Host Controller: A USB is managed by a host controller. The host controller is a chip that manages connected USB devices, allocates bandwidth, coordinates data transfers, ensures backward compatibility and speed management, and oversees power distribution to devices. The USB host controller manages multiple ports on the same bus, with up to 127 devices per controller, though most PCs use several controllers to manage bandwidth better.  

  • USB Standards: USB standards have evolved over time to provide faster data transfer rates and better performance, with each new version introducing improvements. 

  • USB 2.0 HighSpeed: Offers a data transfer rate of up to 480 Mbps, but is half-duplex, meaning devices can only send or receive data, not both simultaneously. 

  • USB 3.2 Gen 1 (SuperSpeed USB): Provides a transfer rate of up to 5 Gbps and is full-duplex, allowing devices to send and receive data at the same time. It uses connectors like USB-A, USB-C, and USB Micro. 

  • USB 3.2 Gen 2x1 (SuperSpeed USB 10 Gbps): Doubles the data rate to 10 Gbps, also supporting full-duplex communication and using USB-A, USB-C, and USB Micro connectors. 

  • USB 3.2 Gen 2x2 (SuperSpeed USB 20 Gbps): Further increases the transfer rate to 20 Gbps by using two 10 Gbps lanes and is typically available with USB-C connectors. 

  • Cable Lengths: Maximum recommended cable lengths are 3 meters for LowSpeed devices and SuperSpeed-capable cables, and 5 meters for FullSpeed and HighSpeed devices.

  • Power Delivery: USB ports supply power alongside data transfer, with basic ports providing up to 4.5 watts, and Power Delivery (PD)–capable ports supplying up to 100 watts, depending on connectors and cabling. 

  • USB Connector Types: Various USB connectors are designed for specific devices and purposes, ensuring proper data transfer and compatibility. 

    • Type A: Commonly used for host connections like computers and hubs; flat and rectangular; USB 3.0 versions have extra pins and are blue for higher speeds. 

    • Type B: Square with a beveled top, typically found on printers and scanners; USB 3.0 versions have more pins and are not backward compatible with older ports. 

    • Mini Type B: Smaller, used on early digital cameras and some portable devices; largely replaced by Micro Type B due to its bulk. 

    • Micro Type B: Compact, used for smartphones and tablets; USB 3.0 version has a dual-plug design for faster speeds. 

    • USB-C: Compact, reversible, supports up to 20 Gbps (USB 3.2 Gen 2x2) and power delivery up to 100 watts; designed for universal use across devices. 

    • Micro Type A and Type B SuperSpeed: Used in USB 3.0 for smaller devices needing high data transfer rates; have extended connectors for extra pins. 

    • Adapter Cables: Allow conversion between different USB types, such as USB-C to USB-A, to maintain compatibility across devices. 

Video Cables 

 

HDMI and DisplayPort are the primary video interfaces used to connect displays to computers and other devices, each offering unique features and capabilities suited to different needs. 

  

  • Video Cable Bandwidth: Bandwidth requirements depend on both the resolution (e.g., 1920x1200 for HD, 3840x2160 for 4K) and frame rate (measured in frames per second or Hz). Higher resolutions and frame rates demand more bandwidth; for example, HD video at 60 fps requires 4.5 Gbps, while 4K video at 60 fps requires 8.91 Gbps. 

 

  •  Display Types: Most computer monitors use LCD/TFT technology with LED backlighting, which provides bright, vibrant colors. Premium displays may use OLED technology, where each pixel emits its own light, offering superior contrast and color accuracy. 

 

  • HDMI (High-Definition Multimedia Interface): HDMI is the most widely used video interface, found in consumer electronics like TVs, gaming consoles, and Blu-ray players, as well as on PC monitors. It supports both video and audio, along with additional features like remote control and High-bandwidth Digital Content Protection (HDCP) for secure content delivery. HDMI versions have evolved to support higher resolutions and advanced features: 

    • Connectors: HDMI has three main connector types—full-size (Type A), mini (Type C), and micro (Type D)—all designed with a beveled shape to ensure proper orientation. 

    • Cable Ratings: HDMI cables are rated by performance—Standard (Category 1) for lower resolutions, High Speed (Category 2) for 4K and refresh rates over 60 Hz. Premium High Speed cables (up to 18 Gbps) and Ultra High Speed cables (up to 48 Gbps) support the latest HDMI 2.0 and 2.1 standards, enabling 8K resolution and enhanced gaming features like variable refresh rate (VRR). 

    •  Audio Support: HDMI can transmit both audio and video signals over a single cable, making it ideal for devices with built-in speakers. However, the video card must include an audio chipset for this functionality to work. 

  • DisplayPort: Developed by the Video Electronics Standards Association (VESA) as a royalty-free alternative to HDMI, DisplayPort is often used in PC graphics cards and professional monitors. It supports many of the same features as HDMI, including 4K resolution, audio, and content protection, but also offers some distinct advantages: 

    •  Connectors: DisplayPort has full-size (DP++) and Mini DisplayPort (MiniDP or mDP) connectors, both designed with a key to prevent incorrect orientation. 

    • Bandwidth and Lanes: DisplayPort uses bonded lanes for data transfer, with up to four lanes available. The original lane bitrate was 2.7 Gbps, and with version 2.0, it has increased to 20 Gbps per lane, allowing for high data throughput. 

    •  Daisy-Chaining: Unlike HDMI, DisplayPort supports daisy-chaining, which allows multiple monitors to be connected to a single video output port, reducing the need for multiple ports on a video card. 

Display Port

Both HDMI and DisplayPort have adapted to meet modern requirements for high-definition and multi-display setups, with HDMI offering broad compatibility across consumer devices and DisplayPort providing advanced features suited for professional and multi-monitor environments. 

Lighting and Thunderbolt Connectors 

Thunderbolt and Lightning cables are advanced interfaces primarily associated with Apple devices but are also used on other platforms for high-speed data and video transfer. 

  • Thunderbolt Interface: Thunderbolt serves as both a display interface (like DisplayPort or HDMI) and a general peripheral interface (like USB). Thunderbolt 1 and 2 use the same physical interface as Mini DisplayPort (MiniDP) and can be used with DisplayPort monitors via adapters, supporting data rates up to 20 Gbps and daisy-chaining multiple monitors.

  • Thunderbolt 3, however, uses the USB-C form factor and supports data transfer rates up to 40 Gbps over short, high-quality cables. While Thunderbolt 3 ports can accept USB devices, Thunderbolt devices require Thunderbolt-enabled USB-C ports, identified by a lightning bolt icon. 

Thunderbolt connector

  • Compatibility and Evolution: Thunderbolt 3 and USB-C use the same connector, but not all USB-C ports support Thunderbolt 3. It is important to check for the flash icon or consult system documentation to confirm compatibility. Newer standards, such as USB 4 and Thunderbolt 4, have been developed and are now emerging in the market.

Lightning cable

Lightning Interface: This is a proprietary interface developed by Apple, used exclusively on their iPhone and iPad devices. The Lightning connector is compact and reversible, making it easy to use. To connect an Apple device with a Lightning port to a PC, an adapter cable like Lightning-to-USB A or Lightning-to-USB C is required. 

Thunderbolt and Lightning interfaces provide versatile and high-speed connectivity options, with Thunderbolt becoming more widely adopted beyond Apple devices and Lightning remaining specific to Apple's mobile ecosystem.

Summary 

Congratulations on completing this lesson on peripheral devices and connectivity! You've explored various I/O ports and connectors that enable devices to communicate with a PC, including USB standards, SATA and Molex cables for storage drives, and HDMI, DisplayPort, Thunderbolt, and Lightning interfaces for video and data transfer. This knowledge equips you to handle device installations and upgrades effectively, ensuring smooth operation in any computer setup. Great job, and as you move on to the next lesson, use the study guides to reinforce what you've learned!