Device Interfaces

Computer Port & Connectors

Whether the computer is a desktop or laptop, the system case contains the computer motherboard. The motherboard connects all the other computer components together. One of its functions is to provide the ports used to attach peripheral devices and cabling to the computer. These Input/Output (I/O) ports are positioned so that they appear through holes cut in the case.

Computer Port & Connectors

USB & Firewire

The Universal Serial Bus (USB) has become the standard means of connecting peripheral devices to a computer. USB devices are Plug-and-Play. This means that when a device is connected via the port, Windows can identify the device and try to install a driver for it (make the device usable) automatically. Another feature of USB is that devices are hot-swappable.

USB & Firewire

This means that Windows can detect and configure a device without requiring a restart.

As well as providing a data connection, USB can supply enough power (about 4.5W) over the cable to run small devices. Devices that require more power than this, such as optical drives or printers, must be connected to an external power supply.

USB Ports & Connectors

There are several types of USB connector:

• Type A—for connection to the host. The connector and port are shaped like flat rectangles.

• Type B—for connection to a device. The connector and port are square, with a beveled top. There are also small form factor versions of the type B connector and port:

USB Ports & Connectors

• Type B Mini—a smaller connector for connection to a device. This type of connector was seen on early digital cameras but is no longer widely used.

• Type B Micro—an updated connector for smaller devices, such as smartphones and tablets. The micro connector is distinctively flatter than the older mini type connector.

• Type C—a new reversible connector type (can be inserted either way up).

USB Ports & Connectors

• Type A and B USB connectors are always inserted with the USB symbol () facing up. Type C (USB-C) connectors are reversible (can be inserted either way up). There are various converter cables with different connector types on each end (for example, a USB Type A to USB-C cable).

USB Data Rates

• The data rate for USB 1.1 is 12 Mbps (megabits per second) while the USB 2.0 (Hi-Speed) standard has a nominal data rate of 480 Mbps. USB 2.0 uses the same connectors as USB 1.1, but a USB 1.1 device plugged into a USB 2.0 port will operate at the lower speed.

USB Data Rates

• The USB 3.0 standard introduces a SuperSpeed mode. SuperSpeed improves the bus bandwidth tenfold (to 5 Gbps or 5000 Mbps) and makes the link full duplex, so a device can send and receive at up to 5 Gbps simultaneously. USB 3.x receptacles and connectors often have a blue connector tab or housing to distinguish them.

USB Data Rates

• USB 3.1 defines a SuperSpeed+ mode with a data rate of 10 Gbps.

  At the time of writing, USB 3.2 is the new standard that replaces the USB 3.1 standard with 2 new SuperSpeed+ transfer modes using two-lane operation, with data rates of 10 and 20 Gbps.

Firewire

• The Firewire bus was based on the IEEE 1394 standard and the Small Computer System Interface (SCSI) communications protocol. Firewire was a competitor to USB but never received mainstream support amongst PC vendors. It was used on some Apple Mac computers. If you do encounter a Firewire device and the motherboard does not provide Firewire ports, an expansion card can be fitted.

Firewire

• This is the symbol used to denote a Firewire Port:

  A single bus can connect up to 63 devices. Like USB, the bus is powered and supports hot swapping.

  The Firewire 400 standard used 6-pin "alpha" connectors and cabling. The 6-pin connectors slightly resemble USB but have a beveled edge on one side. There is also a 4-pin unpowered connector.

• The maximum transfer rate is 400 Mbps.

  The IEEE 1394b (Firewire 800) standard supported transfer rates up to 800 Mbps. Firewire 800 used 9-pin ("beta") connectors and cabling

Graphic Devices

• While USB is used to connect a wide range of different peripheral devices, including keyboards, mice, scanners, cameras, and printers, at the time of this writing, it is not used to connect the computer display or graphics device. The graphics interface can be provided by a number of different technologies.

Multiple Choice

Which USB standard has a rate of 480 Mbps?

• USB 2.0

• USB 1.0

• USB. 1.1

• USB 3.0

Graphic Devices

• A computer's graphics system involves some sort of display unit, such as a flat-panel screen, connected to the computer via a video card (or graphics adapter). The video card generates the signals to send to the screen and provides support for one or more connection interfaces. Low-end graphics adapters are likely to be included as part of the motherboard or CPU. If a computer is to be used for 3D gaming or multimedia work, a better-quality expansion adapter is required.

Graphic Devices

• This is often one of the key features distinguishing budget desktops and laptops from premium versions.Most graphics adapters are based on chipsets by ATI/AMD (Radeon chipset), nVIDIA (GeForce and nForce chipsets), SiS, VIA, and Intel.

Resolution & Color Depth

• A computer image is made up of a number of pixels. The number of horizontal and vertical pixels gives the resolution of the image. Each pixel can be a different color. The total number of colors supported in the image is referred to as the color depth (or bit depth).

Resolution & Color Depth

• The other important component of video is the speed at which the display is refreshed, measured in Hertz (Hz). Increasing any one of these factors increases the amount of bandwidth required for the video signal and the amount of processing that the CPU or GPU (Graphics Processing Unit) must do and the amount of system or graphics memory required

Resolution & Color Depth

• IBM created VGA (Video Graphics Array) as a standard for the resolution and color depth of computer displays. VGA specifies a resolution of 640x480 with 16 colors (4-bit color) at 60 Hz. The VGA standard is long obsolete but was further developed by the Video Electronics Standards Association (VESA) as Super VGA (SVGA).

Multiple Choice

Which statement about Firewire or USB is true?

• USB is based on the Small Computer System Interface protocol.

• USB 1.1 has a maximum transfer rate faster than Firewire.

• Both ends of a Firewire cable are the same.

• USB is based on the IEEE 1394 standard.

Resolution & Color Depth

• SVGA was originally 800x600 @ 4-bit or 8-bit color. This was very quickly extended as the capabilities of graphics cards increased with the de facto XGA standard providing 1024x768 resolution, better color depths (16- and 32-bit), and higher refresh rates.

Resolution & Color Depth

• Resolutions for modern display systems use some variant of the XGA "standard" (in fact, these are labels rather than standards). Most computer displays now use a widescreen form factor (16:9 or 16:10) with a High Definition (HD) resolution such as 1280x720, 1360x768, 1600x900, or 1920x1080 (Full HD). Larger display devices are likely to use even higher resolution, such as 3840x2160 (4K or Ultra HD).

Graphic Device Interfaces

• There are many different types of graphic device/display connectors and cabling. Many video adapters and display screens come with more than one type. When computers were primarily used with Cathode Ray Tube (CRT) monitors, the graphics adapter would generate an analog video signal to drive the monitor. Now that most screens use flat-panel technology, the video signal is usually digital.

HDMI

• The High Definition Multimedia Interface (HDMI) is the most widely used graphic device interface. It is ubiquitous on consumer electronics, such as televisions and Blu-Ray players, as well as computer equipment. HDMI supports both video and audio digital streams, plus remote control (CEC) and digital content protection (HDCP).

HDMI

• HDMI cabling is specified to different HDMI versions, the latest being 2.1. Newer versions support higher bandwidths and consequently better resolutions (4K UHD for instance). HDMI uses a proprietary 19-pin (Type A) connector. HDMI v1.3 introduced the Mini HDMI connector (Type C) for use on portable devices, such as camcorders. This is more compact but has the same number of pins. HDMI v1.4 also introduces the even smaller Micro HDMI connector (Type D), still with 19 pins.

Display and Thunderbolt

• HDMI was principally developed by consumer electronics companies (Hitachi, Panasonic, Sony, and so on) and requires a royalty to use. DisplayPort was developed by VESA, the organization largely representing PC graphics adapter and display technology companies. It is a royalty-free standard intended to "complement" HDMI.

Display and Thunderbolt

• DisplayPort uses a 20-pin connector. A DP++ port allows a connection with DVI-D and HDMI devices (using a suitable adapter cable). There is also a mini DisplayPort format (MiniDP or mDP), developed by Apple and licensed to other vendors.

Display and Thunderbolt

• The Thunderbolt (TB) interface was developed by Intel and is primarily used on Apple workstations and laptops. Thunderbolt can be used as a display interface (like DisplayPort) and as a general peripheral interface (like USB or Firewire). In its first two versions, Thunderbolt uses the same physical interface as MiniDP and is compatible with DisplayPort, so that displays with a MiniDP port can be connected to a host via Thunderbolt. TB ports are distinguished from MiniDP by a lightning bolt icon.

Display and Thunderbolt

• Version 2 of the standard supports links of up to 20 Gbps. Up to six devices can be connected to a single port by daisy-chaining the devices. You can also use a dock or hub device to channel a variety of ports (TB, USB, HDMI, and Ethernet for instance) via a single Thunderbolt port on the host PC or laptop.

Display and Thunderbolt

• Thunderbolt version 3 changes the physical interface to use the same port, connector, and cabling as USB-C. Converter cables are available to connect Thunderbolt 1 or 2 devices to Thunderbolt 3 ports. A USB-C device or cable plugged into a Thunderbolt 3 port will function normally, but it will not support Thunderbolt's features.

Display and Thunderbolt

• A Thunderbolt 3 device plugged into a regular USB Type-C port also will not support Thunderbolt features, and might not work at its optimal level. Thunderbolt 3 supports up to 40 Gbps over a short, high-quality cable (up to 0.5m/1.6ft).

Digital Visual Interface (DVI)

• Digital Visual Interface (DVI) is a high-quality digital interface designed for flat-panel display equipment. There are several types of DVI. The pin configuration of the ports and connectors identifies what type of DVI is supported.

Digital Visual Interface (DVI)

• Single- or dual-link—dual-link makes more bandwidth available. This may be required for resolutions better than HDTV (1920x1200).

• Analog and/or digital—DVI-I supports analog equipment (such as CRTs) and digital. DVI-A supports only analog equipment, and DVI-D supports only digital.

DVI has been superseded by HDMI and DisplayPort/Thunderbolt but was very widely used on graphics adapters and computer displays. HDMI is backward-compatible with DVI-D using a suitable adapter cable. This means that (for example) a DVI-D graphics adapter could be connected to an HDMI port on the display device.

Video Graphics Array (VGA)

• The distinctive blue, 15-pin Video Graphics Array (VGA) port (HD15F/DE-15) is a legacy analog video interface for PC devices. Many graphics adapters and display screens continue to support it.

Multiple Choice

Who created DisplayPort?

• Intel

• Apple

• Advanced Micro Devices (AMD

• Video Electronics Standards Association (VESA)

Video Graphics Array (VGA)

• The connector is a D-shell type (HD15M) with screws to secure it to the port. The interface is analog, meaning that it carries a continuous, variable signal. The interface carries Red, Green, and Blue (RGB) component video signals. As this signal must be converted to work with digital displays, VGA is not very efficient and is not as reliable as other interfaces at supporting high resolutions.

Multiple Choice

What type of device would you connect using a Digital Visual Interface (DVI) port?

• An oscilloscope

• A Blu-Ray player

• A form of flat-panel display equipment

• A Cathode Ray Tube (CRT) monitor

Input Devices

• Input devices, or Human Interface Devices (HID), are peripherals that enable the user to enter data and select commands.

Keyboard

• The keyboard is the longest serving type of input device. Historically, keyboards used the PS/2 interface, which had a round connector with pins. A keyboard PS/2 port is colored purple to differentiate it from the otherwise identical mouse connector. Modern keyboards use USB or Bluetooth ports however.

Keyboard

• Extended PC keyboards feature a number of special command keys. These include ALT and CTRL plus keys such as PRINT SCREEN, NUM LOCK, SCROLL LOCK, START, SHORTCUT, and FUNCTION. Multimedia keyboards may also feature programmable keys and buttons that can be used for web browsing, playing CD/DVDs, and so on.

Multiple Choice

What is the standard resolution of the Video Graphics Array (VGA)?

• A resolution of 1280x720 with 16-bit or 32-bit color

• A resolution of 640x480 with 4-bit color

• A resolution of 800x600 with 4-bit or 8-bit color

• A resolution of 1024x768 with 16-bit or 32-bit color

Mouse

• The mouse is the main type of input device for graphical software. It is an example of a class of input devices described as pointing devices. A pointing device is used to move an on-screen cursor to select screen objects and text.Mice can use PS/2 (the one for the mouse is color-coded green), USB, or Bluetooth connections. There are three distinct types of mice:

Mouse

• Mechanical mouse—this contains rollers to detect the movement of a ball housed within the mouse case. As the user moves the mouse on a mat or other firm surface, the ball is moved and the rollers and circuitry translate that motion to move a cursor on the screen. Mechanical mice are no longer in production.

• Optical mouse—this uses LEDs to detect movement over a surface.

• Laser mouse—this uses an infrared laser, which gives greater precision than an optical mouse.

Mouse

• Another distinguishing feature of different mouse models is the number of buttons (between two and many), which can be customized to different functions, and the presence of a scroll wheel, used (obviously) for scrolling and as a clickable extra button. Mice are also distinguished by their size and shape. Smaller mice are useful with portable systems; some mice are marketed on the basis of their ergonomic shape.

Multiple Choice

Your keyboard no longer works and is not fixable. You look in the closet and find an old dusty keyboard with a cable that ends in a 6-pin purple-colored connector. What type of connector have you found?

• USB

• Bluetooth

• VGA

• PS/2

Laptop Keyboards & Touchpads

• Laptops have built-in keyboards. On smaller laptops, the keyboard may not feature full size keys, which can make typing difficult. Laptop keyboards do not often have numeric keypads either. Instead, the keypad functions are accessed using the FN (Function) key or by toggling NUM LOCK.

Laptop Keyboards & Touchpads

• The FN key also accesses laptop specific functions indicated by distinctive color-accented icons. These include switching the display output between the built-in screen and a connected monitor, adjusting the screen brightness, switching to battery power, disabling wireless functions, and so on.

Laptop Keyboards & Touchpads

• None of the input devices on a laptop are really suitable for sustained use. An external keyboard and/or mouse can of course be connected using a USB or Bluetooth port.

Multiple Choice

You have recently upgraded from a USB mouse to a wireless mouse. Once you remove the old mouse, what do you need to install to connect the wireless mouse to the computer?

• PS/2 adapter

• USB card

• A wireless adapter

• A NIC card

Stylus Pen

• A stylus pen can be used with a compatible touch display or graphics tablet. The stylus can be used like a mouse to select commands, but its main functions are for handwriting and drawing. Most touchscreens are now operated primarily with fingers rather than a stylus. Styluses for art applications can be fitted with nibs of different thicknesses and characters.

Configuring Peripherals

• Peripheral devices can be configured using a mixture of the properties dialogs provided for standard Windows device drivers and the vendor's own driver (if available).

Configuring a Mouse

• Mice can be installed on PS/2, USB, or wireless ports depending on the model.

  • PS/2—connect the mouse to the PS/2 port marked with a mouse icon (usually color-coded green) then switch on the PC.

  • USB—connect the mouse to any USB port. USB is hot-swappable so you can attach the mouse when the computer is already switched on.

  • Wireless—make sure the computer has a working wireless adapter and put a charged battery in the mouse. The mouse generally needs to be synchronized with the receiver using a push button (check the instructions for details) or paired with a Bluetooth receiver.

Configuring a Mouse

• A standard mouse does not need a special driver installing and basic settings can be configured using the Mouse applet in Control Panel/Settings. However, to access and configure extra buttons on some mice you will need to install the manufacturer's driver.

Configuring a keyboard

• A keyboard is connected in the same way as a mouse. You use the Keyboard applet in Control Panel to configure it.

  The main options are to set the repeat rate and sensitivity for keys.

  Multimedia keyboards will also have programmable keys and key combos

Keyboard Regionalization

• PC keyboards can vary from country to country. Where a country uses the Latin alphabet, the variations may be minor. For example, US and UK keyboards vary only in the location of some of the symbols. A keyboard that uses a non-Latin alphabet is considerably different, of course. The type of keyboard layout is configured through the Language applet in Control Panel/Settings, so that the computer knows which symbol to use when a particular key or key combination is pressed.

Keyboard Regionalization

• PC keyboards can vary from country to country. Where a country uses the Latin alphabet, the variations may be minor. For example, US and UK keyboards vary only in the location of some of the symbols. A keyboard that uses a non-Latin alphabet is considerably different, of course. The type of keyboard layout is configured through the Language applet in Control Panel/Settings, so that the computer knows which symbol to use when a particular key or key combination is pressed.

Bluetooth

• Bluetooth is used for so-called Personal Area Networks (PAN) to share data with a PC, connect to a printer, use a wireless headset, connect to a wireless mouse/keyboard, and so on. Bluetooth is a radio-based technology, but it is designed to work only over close range.

Multiple Choice

What type of device would you connect using a Digital Visual Interface (DVI) port?

• A Cathode Ray Tube (CRT) monitor

• A form of flat-panel display equipment

• An oscilloscope

• A Blu-Ray player

Bluetooth

• Bluetooth is quoted to work at distances of up to 10 meters (30 feet) for Class 2 devices or one meter (three feet) for Class 3 devices. There are also Class 1 devices that work at a range of 100m, but these are restricted to industrial applications. At the time of writing, devices supporting the Bluetooth 2.0—Enhanced Data Rate (EDR) standard have a maximum transfer rate of 3 Mbps; otherwise the maximum rate is 1 Mbps.

Configuring Bluetooth

• To set up Bluetooth, you need to "pair" or "bond" the device with the computer. This is done by putting the devices into discoverable mode.

• On devices such as mice and keyboards this is normally done by pressing a recessed switch.

• In Windows, you manage Bluetooth devices using the Settings app. Click the Devices category and select the Bluetooth & other devices tab. There should also be an icon for Bluetooth in the notification area to provide easy access to the configuration settings

Configuring Bluetooth

• On a smartphone or tablet, Bluetooth devices are configured via Settings > Bluetooth.

• Switch Bluetooth on to make the device discoverable and locate other nearby devices. Some devices use an authentication passcode for security.

Multiple Choice

Who created Mini DisplayPort?

• Intel

• Apple

• IBM

• VESA

Configuring Bluetooth

• Devices such as a keyboard, mouse, or headset typically do not have a passkey.

• Devices without a keypad are typically preconfigured with a passkey. Check the product documentation to find the passkey and enter that key on the source computer.

• Many devices are configured to automatically generate a passkey when a connection request is received. This passkey will be shown on both the source and destination device. Input or confirm the key on both devices to accept the connection.

Disabling Bluetooth

• Bluetooth can be disabled quickly via the notification shade in iOS or Android. On a PC, you can use the Bluetooth icon in the notification area to change settings and make the computer non-discoverable. The Bluetooth radio can also be switched on or off using the Wi-Fi adapter toggle.

RF and Near Field Comm (NFC)

• Radio Frequency ID (RFID) is a means of tagging and tracking objects using specially-encoded tags. When an RFID reader scans a tag, the tag responds with the information programmed into it. A tag can either be an unpowered, passive device that only responds when scanned at close range (up to about 25m) or a powered, active device with a range of 100m.

RF and Near Field Comm (NFC)

• Passive RFID tags can be embedded in stickers and labels to track parcels and equipment and are used in passive proximity smart cards.

Multiple Choice

For which reason would you use a Bluetooth Class 1 device with a range of 100m?

• For an automobile hotspot

• As an industrial application

• To connect to a wireless printer

• To connect to a wireless keyboard

RF and Near Field Comm (NFC)

• Near Field Communications (NFC) is a peer-to-peer version of RFID; that is, an NFC device can work as both tag and reader to exchange information with other NFC devices. NFC normally works at up to two inches (six cm) at data rates of 106, 212, and 424 Kbps. NFC sensors and functionality are starting to be incorporated into smartphones. NFC is mostly used for contactless payment readers, security ID tags and shop shelf edge labels for stock control. It can also be used to configure other types of connection (pairing Bluetooth devices for instance).

Networking Interfaces

• Networking interfaces allow computers to be connected to exchange data. Most computers have a local network adapter or Network Interface Card (NIC) already installed as part of the motherboard chipset. A local network adapter (or Ethernet adapter) allows the computer to join a wired network with other nearby computers by connecting the devices to the same Ethernet switch, or switched fabric in an enterprise network. The computer is also likely to be able to access the Internet via the local network connection

Telephone Connector

• While local networking uses Ethernet technologies, some networking and communications functions depend on direct use of the telephone network. Not many computers and laptops ship with a dial-up/analog modem anymore, but they are still often a feature of "all-in-one" print/scan/fax devices. If required, a modem could be added to a PC using an expansion card or to a laptop using a USB fax modem adapter.

Telephone Connector

• A fax modem uses twisted pair cabling with an RJ-11 connector at the fax end and a connector suitable for use with the country's phone system at the other end. This could be another RJ-11 connector, but different connectors may be used in different regions; for example, a BT phone plug would be used in the UK.

Multiple Choice

You have a new Apple workstation and you are looking for a port on the machine where you can plug in either a monitor or a peripheral. What type of port would you use?

• Thunderbolt

• USB

• DisplayPort

• HDMI

Telephone Connector

• The RJ-11 connector is smaller than the RJ-45 connector so you cannot plug one into the wrong port.You are also likely to encounter RJ-11 ports on the DSL (Digital Subscriber Line) modem/router appliance used to connect a home network to the Internet. The Internet or Wide Area Network (WAN) port on the router will be the RJ-11 type. This is connected to the DSL port on the telephone master socket to create a fast, always-on "broadband" Internet link over the telephone line

Multiple Choice

You have a new external hard drive. Which of these ports could be used to connect to the device?

• RJ-11

• RCA

• Thunderbolt

• RJ-45