Installing Motherboards and Connectors

Cable Types and Connectors

Personal Computers

PCs can be purchased as all-in-one units, where internal components are within a case that is also a monitor.

• Typical PC case features:
  • Optical Disc Drive / Unused Optical Disc Drive Bays
  • Front I/O Panel (audio and USB)
  • Power Button
  • Temperature Display on Case
  • Fan Vents for Airflow
• Rear panel features:
  • Power Supply with Fan
  • Chassis Fan
  • Airflow Cutout
  • Motherboard I/O Panel
  • Expansion Card Slot (in use/not in use)

Peripheral Devices

Peripheral cables connect external devices to the computer.

Interfaces, Ports, and Connectors

Interface, port, and connector design ensures correct cable insertion via keying.

Binary Data Storage and Transfer Units

• 1 bit = 1 or 0
• 1 byte = 8 bits
• 1 Kilobyte (KB) = 1000 bytes
• 1 Megabyte (MB) = 1000 KB
• 1 Gigabyte (GB) = 1000 MB
• 1 Terabyte (TB) = 1000 GB

Universal Serial Bus Cables

USB ports allow connection of external devices and can also supply power. The USB port symbol identifies supported features like transfer rates and power delivery.

USB Standards

• USB 1.1 (12 Mbps): Standard Speed
• USB 2.0 (480 Mbps): High Speed
• USB 3.2 Gen 1 (5 Gbps): SuperSpeed
• USB 3.2 Gen 2 (10 Gbps): SuperSpeed+
• USB 3.2 Gen 2x2 (20 Gbps)

USB 3 controllers feature two sub-controllers: one for SuperSpeed and another for legacy HighSpeed, FullSpeed, and LowSpeed devices.

USB Connector Types

• Type-A: The standard flat connector found on most computers.
• Type-B: Used for connecting larger peripherals like printers.
• Type-B Mini: A smaller version of Type-B, used for some mobile devices.
• Type-B Micro: A smaller version of Type-B, commonly used on smartphones. More durable than Type-B Mini.
• Type-C: A reversible connector used for both hosts and devices. Supports USB 3.1 and Power Delivery.

Type-A to Type-A cables are not typically used.
Type-A to Type-B or Type-A to Type-C cables are common.
Type-B and Type-C ports are physically different to prevent incorrect connections. Earlier Type-B 1.1 and 2.0 cables can be used with the Type-B port.

USB Cable Length

Cable length affects data speeds; beyond a certain length, SuperSpeed may drop to HighSpeed.

Power

USB ports supply power to connected devices; basic USB ports can supply up to about 4.5 watts, depending on the version.

HDMI and DisplayPort Video Cables

USB Type-C connections support DisplayPort Alternate Mode, allowing video output.
Video cable performance is determined by three factors:

• The resolution the cable supports (e.g., 1920x1080 at the typical refresh rate of 60 Hz).
• The speed the cable can transfer data; this is described as bandwidth, measured in bits per second (bps).
• Support for features like High Dynamic Range (HDR).

The frame rate in fps describes the video source, while hertz is the refresh rate of the display device & video interface. To avoid artifacts such as ghosting or tearing, the refresh rate should match the frame rate or be evenly divisible by it.

Newer display interfaces use cables with better shielding.
OLED (Organic LED) type offer increased contrast ratio, where each pixel is its own light source.
Support for audio is useful because most TVs and monitors have built-in speakers. The video card must have an audio chipset for this to work, however.

There are Mini Type-A, Type-C connectors which allows the device to easily connect cables.

HDMI connector and port and mini-HDMI connector and port

Ensure use of either Category 1 (standard) / Category 2 (high-speed) cables.
Category 2 cables support increased bandwidth and are recommended for 4K or higher resolution displays.
Check supported version to align with display such as 2.0 or 2.1 specification which offers high-speed up to 48 Gbps.

DisplayPort Interface

Developed by the VESA consortium, DisplayPort is designed as a royalty-free interface. DisplayPort supports more features than HDMI and is intended to replace VGA and DVI.

There are different DisplayPort connector types. Those that are keyed prevents incorrect connections.

Thunderbolt and Lightning Cables

Although the Thunderbolt and Lightning connectors are based on the same physical connector as USB-C, there are key differences.

Thunderbolt Interface

Thunderbolt can be used to daisy chain multiple displays and high speed peripheral devices including USB.
Thunderbolt connectors 1 & 2 use the same physical connector as Mini DisplayPort.
Thunderbolt connectors 3 & 4 use the USB-C connector.
Thunderbolt offers increased performance and is supported as an external PCI Express bus over a cable. Daisy chaining allows a single port by initially connecting peripheral

Thunderbolt 2 supports bandwidth up to 20 \frac{Gb}{s}, while DisplayPort bandwidth is dependent on the version.

Thunderbolt 3 supports up to 40 \frac{Gb}{s}, and offers increased flexibility.

Thunderbolt connectors share the physical connector of the the USB-C, however the Thunderbolt 1 & 2 connectors use the same physical connector as Mini DisplayPort. Legacy adapters exist that allows USB-C devices to function to Thunderbolt/Thunderbolt devices.

Thunderbolt 4 supports up to 40 \frac{Gb}{s}, and products are starting to appear on the market.

Lightning Interface

Apple devices use the proprietary Lightning port and connector. The Lightning connector is reversible. The port is only found on Apple devices; connecting such a device to a PC requires an adapter cable such as Lightning-to-USB-A or Lightning-to-USB-C.

SATA Hard Drive Cables

Serial Advanced Technology Attachment (SATA) is the standard means of connecting internal storage drives within a desktop PC. SATA uses cables of up to 1 m in length terminated with compact 7-pin connectors. Each SATA host adapter port supports a single device. The data connector does not supply power.

A separate 15-pin SATA power connector connects the device to the PSU.

The first commercially available SATA standard supported speeds up to 1.5 \frac{Gb}{s}. Revision 2 supported 3 \frac{Gb}{s}, and Revision 3 supports 6 \frac{Gb}{s}.

Molex Power Connectors

While SATA is preferred for new devices, legacy components connect to the power supply unit (PSU) via a Molex connector, which is usually white or clear plastic and has 4 pins. Wire insulation color-coding represents the voltage: Red (5 V), Yellow (12 V), and Black (ground).

Some devices might have both SATA and Molex power connectors.

External SATA

eSATA is a standard for attaching external drives with a 2 m cable. An eSATA cable must be used to connect to an external eSATA port; an internal SATA cable cannot be used.
eSATAp is a nonstandard powered port used by some vendors that is compatible with both USB and SATA with an eSATAp cable. However, the USB interface dominates the external drive market.

Motherboards

The motherboard houses sockets for devices that implement core system functions: compute, storage, and networking. Knowledge of motherboard types, capabilities, and connector types enables efficient component upgrades and repairs.

Motherboard Functions

Computer software and data are processed using binary code. Software runs instructions in the Central Processing Unit (CPU); this is the compute or processing function. Instructions and data require storage. The CPU can only store a limited number of instructions internally. Additional storage for running programs and open data files is provided through system memory. Random-access memory (RAM) storage technology is nonpersistent, meaning devices can only hold data when the PC is powered on. Mass storage devices are used to preserve data when the computer is turned off.

These processing and storage components are connected by bus interfaces implemented on the motherboard. Instructions and data are stored using transistors and capacitors and transmitted between components over the buses using electrical signals. The motherboard's system clock synchronizes the operation of all parts of the PC and provides the basic timing signal for the CPU. Clock speeds are measured in megahertz (MHz) or gigahertz (GHz). Clock multipliers apply a multiplication factor to timing signals for different bus types, allowing different bus types to work at different speeds (or frequencies).

The motherboard type influences system speed and the range of system devices and adapter cards that can be installed or upgraded. There are many motherboard manufacturers, including Super Micro Computer, ASUS, ASRock, EVGA, MSI, Biostar, Foxconn, Gigabyte, Intel, and Dell. Each motherboard supports a specific range of CPUs, principally manufactured by Intel and Advanced Micro Devices (AMD).

Electrical Safety and ESD

When opening the case for upgrades or troubleshooting, follow proper operational procedures to ensure safety and minimize the risk of damage.

Electrical Safety

The PC must be disconnected from the power supply before opening the case.
Additionally, hold the power button for a few seconds after disconnecting the power cord to ensure that all internal components are drained of charge. Do not attempt to disassemble components that are not field repairable, such as the power supply.

Electrostatic Discharge

Use tools and procedures that minimize the risk of damage to sensitive electronic components. Components such as the CPU, system RAM, adapter cards, and the motherboard itself are vulnerable to electrostatic discharge (ESD). A static charge stored on clothes or body can be suddenly released into a circuit. Handle components by their edges or plastic parts, and ideally, use an anti-ESD wrist strap and other protective equipment and procedures.

Motherboard CPU and System Memory Connectors

All motherboards have connector and socket types for system devices, memory, disk drives, and adapter cards.

CPU Sockets

New motherboards are generally released to support the latest CPU models. Intel and AMD use different socket designs. CPU technology changes rapidly, so a given motherboard will only support a limited number of processor models.

The CPU socket has a distinctive square shape. After CPU installation, it is covered by a heatsink and fan. The chipset supports the CPU. This consist of controllers that handle the transfer of data between the CPU and various devices. The chipset is soldered onto the motherboard and cannot be upgraded. The type of chipset determines the choice of processor, the type and maximum amount of RAM, and support for integrated interfaces/ports, such as video, sound, and networking. Interfaces not supported by the chipset can be installed or upgraded as an adapter card.

System Memory Slots

System memory uses random-access memory (RAM). Program code is loaded into RAM so it can be accessed and executed by the processor. RAM also holds data, such as the contents of a spreadsheet or document while it is being modified. System RAM is volatile - it loses its contents when powered off.

System RAM is normally packaged as a dual inline memory module (DIMM) fitted to a motherboard slot. A DIMM slot has catches at either end, is located close to the CPU socket, and is numbered and often color-coded. There are successive generations of DIMM technologies, such as DDR3, DDR4, and DDR5. A DIMM form factor is specific to a particular DDR version. A label next to the slots should identify the type of DIMMs supported. The capabilities of the memory controller and the number of physical slots determine how much memory can be fitted.

Motherboard Storage Connectors

One or more fixed discs installed inside of the PC case provide persistent storage for the operating system, software programs, and data files. Fixed discs use either solid state drive (SSD) or hard disc drive (HDD) technology.

Serial Advanced Technology Attachment Interface

The motherboard will contain several Serial Advanced Technology Attachment (SATA) ports to connect one or more fixed drives. SATA can also be used to connect removable drives, such as tape drives and optical drives (CD/DVD/Blu-ray). SATA devices are installed to a drive bay in the chassis and then connected to a data port via a cable and to the power supply via a SATA power or Molex connector.

M.2 Interface

An SSD can be provisioned in an adapter card form factor, often using an M.2 interface. An M.2 port is oriented horizontally. The adapter card is inserted at an angle and then pushed into place and secured with a screw. M.2 adapters can be different lengths (42 mm, 60 mm, 80 mm, or 110 mm), so it should be checked that any given adapter will fit on the motherboard. Labels indicate the adapter sizes supported. M.2 supplies power over the bus, so a separate power cable is not needed.

External SATA Interface

eSATA is a standard for attaching external drives with a 2 m cable. An eSATA cable must be used to connect to an external eSATA port; an internal SATA cable cannot be used. eSATAp is a nonstandard powered port used by some vendors that is compatible with both USB and SATA with an eSATAp cable. The main drawback of eSATA compared to USB or Thunderbolt external drives is that power is not supplied over the cable. This is not so much of an issue for 3.5-inch drives, however 2.5-inch drives typically do require power, making USB a more convenient option for portable drives.

Motherboard Adapter Connectors

Expansion slots accept plug-in adapter cards to extend the range of functions the computer can perform. There are two main types of expansion slot interface.

Peripheral Component Interconnect Express Interface

PCIe is the mainstream interface for modern adapter cards. It uses point-to-point serial communications, meaning that each component can have a dedicated link to any other component. Each point-to-point connection is referred to as a link. Each link can make use of one or more lanes. The raw transfer rate of each lane depends on the PCIe version supported. Transfer rates are measured in Gigatransfers per second (GT/s). Throughput in GB/s is the rate achieved after loss through encoding is accounted for.

Adapter slots with more lanes are physically longer. Each PCIe adapter card supports a specific number of lanes, typically x1, x4, x8, or x16. Ideally, the card should be plugged into a port that supports the same number of lanes. However, if insufficient slots are available, a card will fit in any port with an equal or greater number of lanes; this is referred to as up-plugging. For example, a x8 card will fit in a x8 or x16 socket. The card should work at x8 but, in some circumstances, may only work at x1. It may also be possible to fit a longer card into a shorter slot, referred to as down-plugging, so long as the card is not obstructed by other features in the case. A slot may support a lower number of lanes than its physical size suggests. The number of lanes supported by each slot is indicated by a label on the motherboard. For example, a slot that is physically x16 but supports only x8 operation will be labelled x16/x8 or x16 @ x8.

All PCIe versions are backwards-compatible. For example, you can connect a PCIe version 2 adapter to a version 4 motherboard or install a version 4 adapter into a version 2 motherboard. The PCIe works at the speed of the lowest version component. PCIe can supply up to 75 W to a graphics card via a dedicated graphics adapter slot and up to 25 W over other slots; an extra 75 W power can be supplied via a PCIe power connector.

Peripheral Component Interconnect Interface

Computers can support more than one expansion bus, often to support older technologies. PCI is a legacy bus type, superseded by PCI Express. PCIe is software compatible with PCI, meaning that PCI ports can be included on a PCIe motherboard to support legacy adapter cards, but PCI cards cannot be fitted into PCIe slots. As with many legacy technologies, PCI uses parallel communications. Most types of PCI are 32-bit and work at 33 MHz, achieving a transfer rate of up to 133 MBps. The earliest PCI cards were designed for 5 V signalling, but 3.3 V and dual voltage cards became more prevalent. To prevent an incompatible PCI card from being inserted into a motherboard slot (for example, a 5 V card in a 3.3 V PCI slot), the keying for the three types of cards is different.

Motherboard Form Factors

The motherboard form factor describes its shape, layout, and the type of case and power supply that can be used, plus the number of adapter cards that can be installed.

Advanced Technology eXtended Form Factor

The ATX (Advanced Technology eXtended) specification is the standard form factor for most desktop PC motherboards and cases. Full-size ATX boards are 12 inches wide by 9.6 inches deep (305 mm x 244 mm). An ATX board can contain up to seven expansion slots. The MicroATX (mATX) standard specifies a 9.6-inch (244 mm x 244 mm) square board; mATX boards can have a maximum of four expansion slots. Most mATX boards can be mounted in ATX cases.

Information Technology eXtended Form Factor

Small form factor (SFF) PCs are popular as home machines and for use as mini servers. SFF PCs often use VIA's Mini-ITX (Information Technology eXtended) form factor. Mini-ITX is 6.7 inches (170 mm x 170 mm) square with one expansion slot. These are designed for small cases, but do note that most Mini-ITX boards can be mounted in ATX cases. There are also smaller Nano-ITX, Pico-ITX, and Mobile-ITX form factors, but these are used for embedded systems and portables, rather than PCs.

Motherboard Installation

The motherboard is attached to the case by using standoffs. These hold the motherboard firmly and ensure no other part of it touches the case. The standoffs are positioned in holes that line up in the same position in the case and the motherboard if they use compatible form factors.

The general procedure for installing a motherboard is as follows:

1. Use the motherboard documentation to familiarize yourself with the specific installation procedure. Check whether any jumper clips need to be adjusted. A jumper is placed over header pins in a particular orientation. For example, there might be a jumper that enables recovery mode. Use anti-static precautions when handling and storing these device. s
2. Orient the board to the oblong I/O cutout at the rear of the case. Prepare the motherboard I/O blanking plate in the correct orientation by removing caps so that USB, audio, and video ports will be uncovered when the board is fitted. Fit the blanking plate to the case by snapping it into the cutout.
3. Insert standoffs into the case to match the hole locations on the motherboard. Standoffs are usually threaded, though older cases might use push-down pegs. There might be a guide standoff attached to the case or all standoffs might come preinstalled. Make sure that corners, long edges, and the center of the board will be supported. Do not add standoffs where there is no corresponding hole in the motherboard.
4. Optionally, add the CPU and memory modules to the motherboard before installing the board in the case.
5. Check the alignment and standoff location again and verify that each standoff is secure. If everything is correct, place the motherboard on the standoffs. Ensure all connection points are aligned.
6. Secure each standoff using the appropriate screw type. Make sure that the board is firm and stable, but do not overtighten the screws or you risk cracking the board.
7. To complete installation, add the power and disc devices to the case, install any add-on adapter cards to the motherboard, and install the data and power connectors.

Selection and installation of power, disk, system memory, and CPU devices are covered in detail in the next lesson.

Motherboard Headers and Power Connectors

In addition to slots and sockets for system devices, motherboards also include connectors for components such as case buttons, speakers, and fans.

Headers

Components on the front and rear panels of the case connect to headers on the motherboard.

• The power button sends a signal that can be interpreted by the OS as a command to shut down rather than switching the PC off. Holding down the power button for a few seconds will cut the power, however.
• Hard drive activity light shows when an internal hard disc is being accessed.
• Audio ports allow speakers and/or headphones and a microphone to be connected to the computer.
• USB ports - Internal USB 2 connections are made via 9-pin headers, which accept up to two 4-pin port connections (the 9th pin is to orient the cable correctly). USB 3 headers use a 2x10 format and can be cabled to two ports.

When disassembling the system, diagram the position and orientation of header connectors. If no diagram is available you must refer to the motherboard documentation or wires.

Power Connectors

The motherboard also contains various connection points for the power supply and fans.

• The main ATX 12V motherboard power connector is a distinctive 20-pin x 12-pin block with square pin receptacles.
• Fan connectors are 3-pin or 4-pin Molex KK format. There will be one for the CPU and one or more for the case fans and components such as memory and video adapters.

4-pin fan connectors support precise fan speed control via a pulse width modulation (PWM) signal carried by the blue wire. 3-pin fans are controlled by varying the voltage.
Fans with a 3-pin connector can usually be used with 4-pin headers, but the system may not be able to accurately control speed in this case.
PWM fans are preferable, as it is easier for a computer to digitally turn them on and off or partially on. This is more precise than the analog method of varying voltage, and newer motherboards are likely to use PWM.

Video Cards and Capture Cards

An expansion card adds functions or ports that are not supported by the integrated features of the motherboard. An expansion card can be fitted to an appropriate PCIe or PCI slot. Some of the main types of expansion card are sound, video, capture, and network.

Video Cards

The video card (or graphics adapter) generates the signal to drive a monitor or projector. Low-end graphics adapters are likely to be included with the motherboard chipset or as part of the CPU itself; this is also referred to as an onboard adapter or onboard graphics. If a computer is to be used for PC gaming, computer-aided design (CAD), or digital artwork, a more powerful video adapter is required. This can be installed as an add-on card via a PCIe slot. Most graphics adapters are based on chipsets by AMD/ATI, NVIDIA, and Intel. Video cards are distinguished by the following features:

• GPU (Graphics Processing Unit): A microprocessor designed and optimized for processing instructions that render 2D and 3D images and effects onscreen. The basic test for a GPU is the frame rate it can produce for a particular game or application. Other performance characteristics include support for levels of texture and lighting effects.
• Graphics memory: Video cards need a substantial amount of memory for processing and texture effects. A dedicated card may be fitted with up to 12 GB GDDR6/GDR7 at the high end; around 4-8 GB would be more typical of current midrange performance cards. Low-end cards use shared memory (that is, the adapter uses the system RAM). Some cards may use a mix of dedicated and shared memory.
• Video ports: The type and number of connectors, such as HDMI, DisplayPort, and Thunderbolt/USB-C.

Most modern cards use a PCIe x16 interface. Dual cards, using two (or more) slots, are also available.

Capture Cards

Where a graphics card generates an output video signal to drive a monitor, a capture card is used to record video input and save it as a type of movie or streaming media file. Many capture cards are designed to record footage from computer games. Some are designed to work with PC games, while others record from game console HDMI sources or from a live camera (webcam) source, such as a camcorder or security camera. Another class of capture card can act as a TV tuner and record video from broadcast TV sources. A capture card can be fitted as an internal PCIe or as an external unit connected via USB/Thunderbolt.

Sound Cards

Audio playback is achieved via speakers or headphones, which connect to a sound card via an audio jack. Sound cards are also used to record input from a microphone. Most audio jacks are 3.5 mm (⅛ inch) mono or stereo jacks; these are also referred to as phone plugs or mini tip-ring-sleeve (TRS) connectors.

Sound cards supporting multiple output channels with an appropriate speaker system can provide various levels of playback, from mono (on legacy systems) or stereo to some type of surround sound. Surround sound uses multiple speakers positioned around the listener to provide a “cinematic” audio experience. A basic sound chip may be provided as part of the motherboard chipset, but better-quality audio functions can be provided as a PCIe or PCI expansion card. Professional-level cards may also feature on-board memory, flash memory storing sound samples(wavetables), and additional jack types for different input sources.

Audio hardware built into a computer may be susceptible to noise from other internal components. For this reason, some higher quality audio interfaces designed for professional use are external units connected via USB or Thunderbolt.

Network Interface Cards

Most computers have an Ethernet network adapter already installed as part of the motherboard chipset. However, there may be occasions when an add-on NIC needs to be installed or an adapter needs to be upgraded to use a different type of network or cabling/connector, such as copper cable versus fiber optic. A dedicated NIC may also provision multiple ports; these can be bonded into a single higher bandwidth link.

A Wi-Fi adapter can be added to connect to a wireless network. Wi-Fi adapters are developed to different 802.11 standards. There are also cards that can connect to cellular data networks.

Legacy Cable Types

As PC designs have evolved over the years, many types of bus interface have been implemented as connectivity solutions for computer components that maximize the performance and functionality at the time. There can be many reasons why computer systems using these older bus types remain in use in the workplace. As you are likely to work in diverse environments over the course of your career, it is important that you be able to support older technologies alongside modern ones.

DVI and VGA Video Cables

HDMI and DisplayPort video interfaces only support digital flat-panel displays. Older video interfaces were used when computer monitors and projectors were predominantly of the cathode ray tube (CRT) type, driven by an analog signal. Digital Visual Interface (DVI) is designed to support both analog and digital outputs, while popular for a period after its introduction in 1999, DVI is no longer in active development. You are only likely to encounter DVI on older display devices and video cards.There are three types of DVI supporting different configurations for single-and dual-link (extra bandwidth) and analog/digital output signalling. The pin configuration of the connectors identifies that type of DVI is supported by a particular port.

• DVI-I supports both analog equipment and digital outputs.
• DVI-A supports only analog output.
• DVI-D supports only digital.

Video Graphics Array Interface

The 15-pin VGA port was the standard analog video interface for PC devices for a very long time. Up until a few years ago, most video cards and monitors included a VGA port, though it is starting to be phased out completely now. VGA will usually support resolutions up to 2048x1536 depending on cable quality. The connector is a D-shell type with screws to secure it to the port.

Small Computer System Interface

Modern bus interfaces such as USB and Thunderbolt use serial communications. These serial links can achieve Gbps and Tbps speeds through the use of improved signalling and encoding methods. Back when serial interfaces were much slower, PC vendors used parallel data transmission to support better transfer rates. While a serial interface essentially transfers 1 bit at a time, a parallel interface transfers 8 bits (1 byte) or more. This requires more wires in the cable and more pins in the connectors, meaning parallel interfaces are bulky. SCSI (Small Computer System Interface) is one example of a legacy parallel bus. One SCSI host bus adapter (HBA) can control multiple devices attached by internal ribbon cables or external SCSI cables. The SCSI standard also defines a command language that allows the host adapter to identify which devices are connected to the bus and how they are accessed. SCSI could be used for both internal devices and external peripherals, such as scanners and printers, but you are now unlikely to find it used for any purpose other than the connection of internal hard disc drives. SCSI could support data rates up to 320 MBps. There have been numerous versions of SCSI, with many different physical connectors, but you are only likely to come across high density 68-pin connectors or single connector attachment (SCA) 80-pin connectors. SCA incorporates a power connector, while HD68 is used with Molex power connectors. Each device on a wide SCSI bus must be configured with a unique ID from 0 to 15. The host adapter is usually set to 7 or 15. A bootable hard disc is usually allocated ID 0. The first and last devices on a SCSI bus must be terminated. Termination may either be enabled internally on the device by setting a switch or by physically connecting a terminator pack to a device or the host adapter.

Additionally, while parallel SCSI as a physical interface has almost completely disappeared, the software interface and command set are used in many other storage technologies, including serial attached SCSI (SAS). SAS is a dominant interface for enterprise-class storage devices in the PC, workstation, and server markets.

Integrated Drive Electronics Interface

The IDE interface was the principal mass storage interface for desktop PCs for many years, the interface is also referred to as parallel advanced technology attachment (PATA). The Extended IDE (EIDE) bus interface uses 16-bit parallel data transfers. A motherboard supporting IDE may come with one or two host adapters, called the IDE1 channel and the IDE2 channel; these may also be labelled primary (IDE0) and secondary (IDE1). A single IDE channel is now more typical if the motherboard also supports SATA. Each IDE channel supports two devices, 0 and 1. An EIDE cable typically has three color-coded connectors. The blue connector is for the motherboard port. The black (end) and grey (middle) connectors attach to devices 0 and 1 respectively. When inserting a connector, pin 1 on the cable must be oriented with pin 1 on the port; on the cable, pin 1 is identified with a red stripe. The connectors are also keyed to prevent them from being inserted the wrong way around.

Many sources call the primary and secondary channels "master" and "slave" respectively. CompTIA and the computing industry generally are working to eliminate this type of non-inclusive terminology, but you will often still see it used in historical support documentation.

Serial Cables

The serial port is a legacy connection interface where data is transmitted over one wire one bit at a time. Start, stop, and parity bits are used to format and verify data transmission; this interface is also referred to as Recommended Standard 232 (RS-232). While modern interfaces like USB are also serial, an RS-232 interface uses much less sophisticated signalling methods. Consequently, an RS-232 serial port supports data rates up to about 115 Kbps only. Serial ports are generally associated with connecting external modems (used to establish dial-up internet connections) though even this function has largely been superseded by USB. You may also come across serial ports on network equipment, where a serial connection can be used to manage the device. RS-232 specifies a 25-pin hardware interface, but in practice PC manufacturers used the cheaper 9-pin D-subminiature (DB-9) female port.

In Windows, the serial port is referred to as a Communications (COM) port.

Another historical port is the PS/2 port, used for connecting a keyboard and mouse. The green PS/2 port is typically for a mouse, and the purple one is for a keyboard.

Adapter Cables

Given the numerous cable types and connector types, it will often be the case that a basic peripheral cable will not provide a connection between a port available on the PC and the port used on the peripheral device. An adapter cable can often be used to overcome this issue. An adapter cable has connectors for two different cable types at each end. An active adapter uses circuitry to convert the signal, while a passive adapter simply converts between two connector form factors.

The following types of adapter cable are typical:

• Video adapters convert between signalling types, such as DVI to VGA, HDMI to DisplayPort, or Mini-HDMI to HDMI.
• USB adapters convert connector types, such as USB-C to USB-A. There are also USB hubs that provide additional ports.
• USB adapters to various kinds of ouput, including Lightning, Mini-HDMI and HDMI.

Guidelines for Motherboard & Peripheral Support

Follow these guidelines to support the installation and configuration of motherboards, peripheral devices, and connectors:

• Make support documentation available for technicians to easily identify the features of system cases and motherboards (especially ATX/ITX form factor), CPU socket type, and header configuration - and perform maintenance and upgrades efficiently.
• Identify requirements for peripheral cables and connector types so that missing or faulty cables can be replaced quickly. Consider stocking adapter cables to use devices even if the connector type is not directly supported by the motherboard.
• Identify opportunities to upgrade legacy interfaces (VGA, DVI, SCSI, PATA/EIDE, PCI, and RS-232 serial) with faster and more reliable modern versions (USB/Thunderbolt, HDMI, DisplayPort, PCIe, SATA, and M.2).
• Identify systems with additional controller and port requirements, research the best video, capture, sound, or network card model to meet said requirements.