COMP 129 (On-Line) Notes
Chapter 1 Introduction to Computer Repair
Chapter Summary * • Computer technicians should actively listen, have a positive attitude, refrain from using technical acronyms and terminology when speaking with nontechnical people, and be culturally sensitive. * • Easily identify important computer parts installed in a computer and as standalone parts: case, keyboard, mouse, motherboard, monitor, power supply, hard drive, optical drive, adapter, riser board, and memory. * • Easily identify various ports to determine what device attaches to them: VGA, DVI, HDMI, DisplayPort, USB, IEEE 1394, 3.5mm sound jack, PS/2, RJ-45, eSATA, parallel, serial, and RJ-11. * • The most popular method for adding functionality to desktops, laptops, and tablets is to use a USB port. * • USB 3.0 ports will accept 3.0 and older devices and provide more power. You can add additional ports by connecting a USB module to motherboard pins. This module takes an expansion space (but not a slot). A PCI/PCIe adapter can also be installed to provide additional ports. Cabling from the power supply to the adapter might be required to provide power to the new USB ports. * • Up to five USB hubs can be daisy-chained to one port. Upstream ports connect to the computer or another USB port. Devices connect to downstream ports. * • USB hubs can be self-powered or bus powered. * • IEEE 1394 devices do not have to have a computer port and can be cabled to each other; otherwise, an IEEE 1394 device can be cabled to a port or a hub. * • USB and IEEE 1394 troubleshooting issues commonly relate to power, drivers, or system resources.

A computer technician must be a jack-of-all-trades: a software expert in various operating systems and applications; a hardware expert in everything ranging from processors to the latest laser printers; a communicator extraordinaire to handle the occasional irate, irrational, or computer-illiterate customer; a good listener to elicit computer symptoms from customers (and from the computer); an empathetic counselor to make customers feel good about their computers and confident in the technician’s skills; and, finally, a master juggler of time and priorities. These traits do not come overnight, and not all of them can be taught—but a technician can constantly develop and fine-tune each of them.
The best quality a technician can possess is logic. A good technician narrows a problem to a general area, subdivides the problem into possible culprits, and eliminates the possibilities one-by-one efficiently and logically. A technician is like a detective, constantly looking for clues, using common sense and deductive reasoning, gathering information from the computer and the computer user, and finally solving the mystery. Detective work is integral to a technician’s job; therefore, throughout this book, Tech Tips provide important technical tips.
CompTIA A+ Certification
An industry-standard certification called A+ is important for technicians, especially new technicians. This certification does not guarantee you a job, but the certification helps you get interviews and proves to companies that you have a higher level of understanding of computers and basic networking. The A+ certification consists of two exams: CompTIA A+ 220-801 and 220-802. You must pass both exams to achieve A+ certification. CompTIA provides official certification objectives for each exam. This book covers all the exam objectives for both exams.
Safety Note
Safety is covered in each chapter, especially in Chapter 4, but no book on computer repair can begin without stating that both the technician and the computer can be harmed by poor safety habits. To protect yourself and the computer, make sure to power off the computer and remove the power cord when disassembling, installing, or removing hardware, or doing preventive maintenance (cleaning). Never take an older CRT monitor or power supply apart unless you have been specifically trained on these components. The MSDS (material safety data sheet) is required to be made available to staff. The MSDS lists safety information such as handling, first aid, storage procedures, and disposal for any potentially harmful substances or materials, including those used with computer cleaning and repair.
Technicians have to be able to lift computers, servers, printers, monitors, and other devices. A common requirement in job advertisements or explained during interviews is in regard to lifting. Technical jobs frequently specify a maximum lifting requirement of 40 to 50 pounds. Use proper safety precautions, such as those shown in Figure 1.1. The type of equipment you need and things that you can do to prevent harm to the computer are covered more explicitly in Chapter 4, on power and disassembly.
Technician Qualities
Three of the most important qualities that a technician can have are active listening skills, a good attitude, and an appropriate level of “tech speak.” Active listening means that you truly listen to what a person (especially one who is having a problem) is saying. Having active listening skills involves good eye contact, nodding your head every now and then to show that you are following the conversation, taking notes on important details, and avoiding distractions such as incoming cell phone calls or other activities. Clarify customer statements by asking pertinent questions and avoid interrupting the customer. Allow customers to complete their sentences. Many technicians jump into a problem the moment they hear the first symptom described by the user. Listen to the entire problem. Do not act superior because you know terms and things that they do not. Ask open-ended questions—questions that allow the user to expand on the answer rather than answer with a single word, such as yes or no. Figure 1.2 illustrates this point.
Basic Computer Parts
Computer systems include hardware, software, and firmware. Hardware is something you can touch and feel—the physical computer and the parts inside the computer are examples of hardware. The monitor, keyboard, and mouse are hardware components. Software interacts with the hardware. Windows, Linux, OS X, Microsoft Office, Solitaire, Google Chrome, Adobe Acrobat Reader, and WordPerfect are examples of software.
Without software that allows the hardware to accomplish something, a computer is nothing more than a doorstop. Every computer needs an important piece of software called an operating system, which coordinates the interaction between hardware and software applications. The operating system also handles the interaction between a user and the computer. Examples of operating systems include Windows XP, Windows Vista, Windows 7, Windows 8, OS X, and various types of Unix, such as Red Hat and Mandrake.
A device driver is a special piece of software designed to enable a hardware component. The device driver enables the operating system to recognize, control, and use the hardware component. Device drivers are hardware and operating system specific. For example, a printer requires a specific device driver when connected to a computer loaded with Windows XP. The same printer will most likely require a different device driver when using Windows 7. Each piece of installed hardware requires a device driver for the operating system being used. Figure 1.4 shows how hardware and software must work together.

Firmware combines hardware and software into important chips inside the computer. It is called firmware because it is a chip, which is hardware, and it has software built into the chip. An example of firmware is the BIOS (basic input/output system) chip. BIOS chips always have software inside them. The BIOS has startup software that must be present for a computer to operate. This startup software locates and loads the operating system. The BIOS also contains software instructions for communication with input/output devices, as well as important hardware parameters that determine to some extent what hardware can be installed. For example, the system BIOS has the ability to allow other BIOS chips that are located on adapters (such as the video card) to load software that is loaded in the card’s BIOS.
The simplest place to start to learn about computer technical support is with the devices themselves. Computer devices come in many shapes and sizes. The PC, or personal computer, comes in desktop models and mobile models, such as a laptops, ultrabooks, and netbooks. The old term Internet appliance was used for any device used to access the Internet. Of course, this is quite common today, as computers, laptops, smartphones, e-readers, tablets, and so on can all access the Internet. Figure 1.5 shows some of the computing devices technical staff are expected to support.
A PC typically consists of a case (chassis), a keyboard that allows users to provide input into the computer, a monitor that outputs or displays information, and a mouse that allows data input or is used to select menus and options. An input device is used to put data into the computer. A microphone, keyboard, mouse, or your finger (when used with a tablet or phone) are great examples. Also, biometric devices can be input devices. Common biometric devices are a finger swipe reader and an integrated camera that can be used for facial recognition to gain access to a device.
An output device such as a monitor accepts data from the computer. Some devices can be both input and output devices, such as a printer or a touch screen. In the case of a printer, data is sent from your computer to the printer, and the printer can send data (information), such as an out-of-ink message, back to the computer. Figure 1.6 lists common input and output devices.
A device that can be both an input device and an output device is a KVM switch. KVM stands for keyboard, video, mouse, and a KVM switch allows connectivity of multiple devices so they can be shared between computers. For example, one keyboard, one mouse, and one display could connect to a KVM switch. A KVM switch has cables that allow it to connect or output to two or more computers.
Once the computer cover or side is opened or removed, the parts inside can be identified. The easiest part to identify is the power supply, which is the metal box normally located in a back corner of the case. A power cord goes from the power supply to a wall outlet or surge strip. One purpose of the power supply is to convert the AC voltage that comes out of the outlet to DC voltage. The power supply distributes this DC voltage using power cables that connect to the various internal computer parts. A fan located inside the power supply keeps the computer cool, which avoids damage to the components.
A personal computer usually has a device to store software applications and files. Two examples of storage devices are the floppy drive and the hard drive. A slot in the front of many older computers easily identified the floppy drive. The floppy drive allows data storage to floppy disks (sometimes called diskettes, or disks) that can be used in other computers. Floppy disks store less information than hard drives. They are also obsolete, for the most part. The hard drive, sometimes called hard disk, is a rectangular box normally inside the computer’s case that is sealed to keep out dust and dirt. An optical drive holds discs (CDs, DVDs, or BDs) that have data, music, video, or software applications on them. Mobile devices such as tablets and smartphones don’t have storage devices such as this.
The motherboard is the main circuit board located inside a PC and contains the most electronics. It is normally located on the bottom of a desktop or laptop computer and mounted on the side of a tower computer. Other names for the motherboard include mainboard, planar, or systemboard. The motherboard is the largest electronic circuit board in the computer. The keyboard frequently connects directly to the back of the motherboard, although some computers have a keyboard connection in the front of the case. Figure 1.7 shows the major components of a tower computer.
A device may have a cable that connects the device to the motherboard. Other devices require an adapter. Adapters are electronic circuit cards that normally plug into an expansion slot on the motherboard. Other names for an adapter are controller, card, controller card, circuit card, circuit board, and adapter board. The number of available expansion slots on the motherboard depends on the manufacturer.
An adapter may control multiple devices, such as the microphone and speakers. An alternative to an adapter plugging directly into the motherboard is the use of a riser board. A riser board plugs into the motherboard and has its own expansion slots. Adapters can plug into these expansion slots instead of directly into the motherboard. Riser boards are used with rack-mounted servers and low-profile desktop computer models. The riser card is commonly inserted into a motherboard slot or attached using screws. Figure 1.8 shows how to install a riser board.
Memory is an important part of any computing device. Memory chips hold applications, part of the operating system, and user documents. Two basic types of memory are RAM and ROM. RAM (random access memory) is the most common in all computing devices and is volatile memory—that is, the data inside the chips is lost when power is removed. When a user types a document in a word processing program, both the word processing application and the document are in RAM. If the user turns the computer off without saving the document to removable media or the hard drive, the document is lost because the information does not stay in RAM when power is removed.
ROM (read-only memory) is nonvolatile memory because data stays inside the chip even when the computer is turned off. ROM chips are sometimes installed on adapters such as a network or video card.
RAM and ROM chips come in different styles: DIP (dual inline package), DIMM (dual inline memory module), and RIMM (a memory module developed by Rambus). Computer and mobile device DIMMs are the most common type of RAM found in computers. Some ROMs are DIP chips. They are usually distinguishable by a sticker that shows the manufacturer, version, and date produced. Memory chips are covered in great detail in Chapter 6. See Figure 1.11 for an illustration of a motherboard, various expansion slots, memory, and an adapter in an expansion slot.
Tablets and smartphones frequently have no field-serviceable parts (parts that can be replaced by a technician) and are typically not upgradable except for memory. Mobile devices and laptops do have RAM. Sometimes this RAM is not upgradable in mobile devices such as tablets and smartphones. However, storage is sometimes available using flash memory. Flash memory is very common with USB-based thumb drives used with PCs and laptops and is nonvolatile—that is, data is not lost when power is removed. Flash memory cards for mobile devices include CompactFlash and various types of SD (Secure Digital) cards: SD, miniSD, microSD, and xD (extreme digital). Figure 1.12 shows a photo of two of these memory cards.
External Connectivity
A port is a connector on a motherboard or on a separate adapter that allows a device to connect to a computer. Sometimes a motherboard has ports built directly into the motherboard. Motherboards that have ports built into them are called integrated motherboards. A technician must be able to identify these ports readily to ensure that (1) the correct cable plugs into each port and (2) the technician can troubleshoot problems in the right area.
Many port connections are either male or female. Male ports have metal pins that protrude from the connector. A male port requires a cable with a female connector. Female ports have holes in the connector into which the male cable pins are inserted.
Some connectors on integrated motherboards are either D-shell connectors or DIN connectors. A D-shell connector has more pins or holes on top than on the bottom, so a cable connected to the D-shell connector can be inserted in only one direction and cannot be accidentally flipped upside down. Many documents represent a D-shell connector by using the letters DB, a hyphen, and the number of pins—for example, DB-9, DB-15, or DB-25.
A mini-DIN connector is round with small holes and is normally keyed. When a connector is keyed, the cable can only be inserted one way. Keyboard and mouse connectors, commonly called PS/2 ports, are examples of mini-DIN connectors. Today, a keyboard and mouse can also be connected to USB ports (as discussed later in the chapter). Figure 1.13 shows the back of a computer with an integrated motherboard. You can see a DIN and two D-shell connectors on the motherboard.
Mouse and keyboard ports have traditionally been 6-pin mini-DIN ports that are sometimes called PS/2 ports. Otherwise, USB ports are used for mouse/keyboard connectivity. Many manufacturers color code the PS/2 mouse port as green and the PS/2 keyboard port as purple and/or put a small diagram of a keyboard or a mouse by each connector. Figure 1.14 shows mouse and keyboard connectivity options.
Mice and Keyboards
There are two basic types of mice—mechanical and optical. A mechanical mouse uses a rubber ball inserted into the bottom of the mouse. The rubber ball turns small metal, rubber, or plastic rollers mounted on the sides. The rollers relay the mouse movement to the computer. On the other hand, an optical mouse has optical sensors that detect the direction in which the mouse ball moves. It uses reflections from LEDs from almost any surface to detect the mouse location. Figure 1.15 shows a photo of mechanical and optical mice.
Keyboards are input devices that connect to the keyboard port. There are two main types of keyboards: mechanical and capacitive. Mechanical keyboards are the cheapest and most common type. They use a switch that closes when a key is depressed. When the switch gets dirty, it sticks. Mechanical keyboards require more cleaning and are more error-prone than their capacitive counterparts. A capacitive keyboard is more reliable and more expensive than a mechanical keyboard because of the electronics involved in the design.
Laptops and netbooks usually have integrated keyboards as well as a variety of mouse replacement devices, such as trackpoint, touchpad, and/or one or two buttons used for clicking and right-clicking. You should always remove the battery and AC power cord before removing a laptop keyboard or any other internal laptop part. To remove a laptop keyboard, you commonly remove screws from the top or bottom of the laptop and slide or lift the keyboard out of the case. Always refer to the manufacturer’s documentation before removing or replacing a laptop keyboard. Figure 1.16 shows the laptop keyboard removal process.
Mobile devices, such as smartphones as well as some desktop displays, use touch and multitouch technologies to allow a finger or a stylus to interface with the operating system. HTC Corporation’s TouchFlo technology allows distinguishing between a finger and a stylus and responds appropriately, depending on the input method used. Swiping is used to go to the next page of applications or go to the next photo. Multitouch technology is simply the ability to accept multiple touches, such as when two fingers or a finger and a knuckle are used. Figure 1.17 shows a couple multitouch techniques.
Table 1.1 Wireless input technologies Technology | Description | Troubleshooting | Infrared | Used for very short distances. Cheaper than other technologies. | Check line of sight; check if device or battery is charged; ensure that no bright light, such as sunlight, is interfering with communication. | Radio | Works in the 27MHz or 2.4GHz frequency range. Longer distances are supported than with infrared. | Check for interference from other devices, including wireless devices on the same frequency. | Bluetooth | Includes 128-bit security and works in the 2.4GHz range. There are three classes of devices, with ranges up to 19.6 feet (6 meters), 72.1 feet (22 meters), and 328 feet (100 meters). Up to eight devices can be connected in a master–slave relationship, with only one device being the master. | Check for interference from other devices, including wireless devices on the same frequency. Also look for Windows, Apple iOS, or Android configuration issues. |
Keyboard/Mouse Troubleshooting
One of the easiest ways to determine whether a keyboard is working is to press the CAPS LOCK
CAPS LOCK or NUMB LOCK
NUMB LOCK key and watch to see if the keyboard light illuminates. If a particular key is not working properly, remove the key cap. The chip-removal tool included with a PC tool kit is great for this. A tweaker (small, flat-tipped) screwdriver also does a good job. After removing the key cap, use compressed air around the sticky or malfunctioning key.
The VGA port was designed for analog output. A mini-VGA port is also available on some mobile devices. A newer port is a DVI port (Digital Visual Interface), and it has three rows of square holes. DVI ports are used to connect flat panel digital displays. Some flat panel monitors can also use the older VGA port. Some video adapters also allow you to connect a video device (such as a television) that has an S-Video port. Figure 1.23 shows a video adapter with all three ports. The top port is for S-Video, the center port is the DVI connector, and the bottom port is a VGA port.
There are several types of DVI connectors, and the one used depends on the type of monitor attached. Two terms used with these DVI connectors are single link and dual link. A single link connection allows video resolutions up to 1920×1080. With a dual link connection, more pins are available to send more signals, thus allowing higher resolutions. The two major types of connectors are DVI-D and DVI-I. DVI-D is used for digital video connectivity only. DVI-I can be used for both digital and analog monitors and is the most common. A less common type is DVI-A, which is not shown in Figure 1.24 with the other DVI connector types.
An upgrade to DVI is HDMI (High-Definition Multimedia Interface), which is a digital interface that can carry audio and video over the same cable. HDMI is found on cable TV boxes, televisions, video adapters, laptops, desktops, and tablets. MiniHDMI or microHDMI connectors are used with such devices as cameras, tablets, and smartphones. Table 1.3 describes the different HDMI ports.
Table 1.3 HDMI ports HDMI connector type | Description | A | 19-pin port found on a TV or PC that can have a Category 1 (standard) or Category 2 (high-speed) cable attached | B | 29-pin port used with very high-resolution displays | C | 19-pin mini port (2.42mm × 10.42mm) found on mobile devices | D | 19-pin micro port (2.8mm × 6.4mm) found on mobile devices |
An RCA jack is used for connections such as to a scanner or camera. Sometimes three RCA jacks are used for composite video, as shown on the top row of projector ports in Figure 1.26. The yellow connection is for video, and the red and white connections are for audio. Higher-quality connections are red, green, and blue RCA jacks for RGB/component video (see Chapter 9). Notice in Figure 1.26 that the projector has similar connections to PCs. Cables that convert between the different ports are available.
Laptops and netbooks have external video ports. To send data out these ports, you have to hold down the Fn
Fn
key and press a specific function key, such as F-8
F-8
or F-12
F-12
, depending on the computer manufacturer. Figure 1.27 shows common symbols you might see on a keyboard.
For Apple iOS devices, you can purchase an Apple Digital AV adapter. This cable is like a Y cable, and the end of the Y attaches to the Apple device. A power connector can connect to one of the Y prongs and an HDMI cable can attach to the other Y prong. TV standards up to 1080p are supported.
Another port that can send and receive audio and video signals is the DisplayPort developed by VESA (Video Electronics Standards Association). The port is designed to primarily output to display devices and can have a passive converter to be used to convert to a single-link DVI or HDMI port. A mini DisplayPort is also available on mobile devices. You use an active converter to convert to dual-link DVI. Figure 1.28 shows the DisplayPort. An exercise at the end of the chapter provides port identification practice with the variety of display ports you might see.
An updated port that uses some of the DisplayPort technology is the Thunderbolt port. The Thunderbolt interface was developed by Intel, with support from Apple. The port used on Apple computers is the same connector as the mini DisplayPort. Figure 1.29 shows a Thunderbolt port and cable.
USB Port
USB stands for Universal Serial Bus. A USB port allows up to 127 connected devices to transmit at speeds up to 5Gbps (5 billion bits per second). Devices that can connect to a USB port include printers, scanners, mice, keyboards, joysticks, optical drives, tape drives, game pads, cameras, modems, speakers, telephones, video phones, data gloves, and digitizers. Additional ports can sometimes be found on the front of a PC case or on the side of a mobile device. Figure 1.30 shows USB ports. USB ports and devices come in three versions—1.0/1.1, 2.0 (Hi-Speed), and 3.0 (SuperSpeed). USB 1.0 operates at speeds of 1.5Mbps and 12Mbps; version 2.0 operates at speeds up to 480Mbps. Version 3.0 transmits data up to 5Gbps. The 3.0 USB port, which still accepts older devices, is colored blue.
USB 3.0 is backward compatible with the older versions, which means that the cables from any 1.0/2.0 device work with a 3.0 port. To achieve USB 3.0 speeds, however, a 3.0 device, 3.0 port, and 3.0 cable must be used. The version 1 and 2 cables used 4 wires. Version 3 cables use 9 wires. Figure 1.31 shows the different version and speed symbols. Note that the port is not required to be labeled, and sometimes looking at the technical specifications for the computer or motherboard is the only way to determine port speed.
Each USB standard has a maximum cable length: * • Version 1.0/1.1: 9.8 feet, or 3 meters * • Version 2.0: 16.4 feet, or 5 meters * • Version 3.0: 9.8 feet, or 3 meters
USB ports are known as upstream ports and downstream ports. An upstream port is used to connect to a computer or another hub. A USB device connects to a downstream port. Downstream ports are commonly known as Type A and Type B. A standard USB cable has a Type A male connector on one end and a Type B male connector on the other end. The port on the computer is a Type A port. The Type A connector inserts into the Type A port. The Type B connector attaches to the Type B port on the USB device. Figure 1.32 shows Type A and Type B connectors. There are also mini versions of these connectors. See Figures 1.36 and 1.46, later in this chapter.
A USB port can have more than one device attached to the port through the use of a USB hub. Many hubs can operate in two power modes—self-powered and bus-powered—and a hub may have a switch control that must be set to the appropriate mode. A self-powered hub has an external power supply attached. A bus-powered hub has no external power supply connected to the hub. Once all USB devices attached to a hub are tested, the hub’s power supply can be removed and the devices retested. If all attached devices work properly, the hub power supply can be left disconnected. Figure 1.33 shows USB hub connectivity, and Figure 1.34 shows USB cabling rules.
USB ports have always been able to provide power to unpowered devices such as flash drives. A charging USB port is a port designed to be able to provide power to run and charge attached devices. Note that not all USB devices can be charged this way. A sleep-and-charge USB port is one in which the port still provides power to the device (power to charge the device) even when the computer is powered off. See the computing device’s specifications to see if a USB ports supports this feature.
USB has expanded into other fields. USB OTG (on-the-go) is a supplement to the USB 2.0 specification. Normally with USB, a device that does not have too much intelligence built into it attaches to a host—specifically, a PC. USB on-the-go allows a USB device, such as an audio player or a mobile phone, to have the capability of being the host device. This allows two USB devices to communicate without the use of a PC or a hub. The supplement allows a USB OTG device to still attach to a PC because USB OTG is backward compatible with the USB 2.0 standard.
Certified W-USB (wireless USB) supports high-speed, secure wireless connectivity between a USB device and a PC, at speeds comparable to Hi-Speed USB. Certified Wireless USB is not a networking technology; it is just another way that you can connect your favorite USB devices to a host. You just don’t have to plug a cable into a USB port. Wireless USB supports speeds of 480Mbps at a range up to 3 meters (~10 feet) or 110Mbps up to 10 meters (~30 feet). Wireless USB uses ultra-wideband low-power radio over a range of 3.1 to 10.5GHz. Figure 1.37 shows the various USB logos that might be found on devices.
Parallel Ports
Parallel ports were used to connect older printers to computers. Some motherboards have a small picture of a printer etched over the connector. Parallel ports transfer 8 bits of data at a time to the printer or any other parallel device connected to the parallel port. Parallel ports are obsolete, having been replaced by USB ports. Figure 1.40 shows a parallel port.
Installing Extra USB Ports
Many motherboards support adding two or more USB ports by using a cable that attaches to motherboard pins otherwise known as a USB header. The ports mount in an expansion slot space but do not take an expansion slot. Even if the motherboard has such pins, the ports and cable assembly might have to be purchased separately. Figure 1.38 shows sample USB ports that attach to a motherboard
Serial Ports
A serial port (also known as a COM port, an RS-232 port, or an asynchronous [async] port) can be a 9-pin male D-shell connector or a 25-pin male D-shell connector (on old computers). Serial ports are used for external analog modems, printers, and some networking equipment. Serial ports, like parallel ports, are obsolete, having been replaced by USB ports.
Figure 1.41 shows two types of serial port markings. Figure 1.42 shows a USB-to-serial port converter you can use if a serial port is needed and only USB ports are available. You can purchase converters to convert almost any other type of port to a USB port.
Audio Ports
A sound card converts digital computer signals to sound and sound to digital computer signals. A sound card is sometimes called an audio card and can be integrated into the mother-board or be on an adapter that contains several ports. The most common ports include a port for a microphone, MP3 player, or other audio device. One or more ports for speakers, a headphone port, and S/PDIF (Sony/Philips Digital Interface) in/out ports are used to connect to various devices, such as digital audio tape players/recorders, DVD players/recorders, and external disc players/recorders. There are two main types of S/PDIF connectors: an RCA jack used to connect a coaxial cable and a fiber-optic port for a TOSLINK cable connection. Sound cards are popular because people want better sound quality than what is available integrated into a motherboard. See Figure 1.43 for an illustration of a sound card.
IEEE 1394 Ports
The IEEE 1394 standard is a serial technology developed by Apple Computer. Sometimes it is known as FireWire (Apple), i.Link (Sony), or Lynx (Texas Instruments). IEEE 1394 ports have been more predominant on Apple computers but are also seen on some PCs. Windows and Apple operating systems support the IEEE 1394 standard. Many digital products have an integrated IEEE 1394 port for connecting to a computer. IEEE 1394 devices include camcorders, cameras, printers, storage devices, video conferencing cameras, optical players and drives, tape drives, film readers, speakers, and scanners.
IEEE 1394 has two data transfer modes—asynchronous and isochronous. The asynchronous mode focuses on ensuring that data is delivered reliably. Isochronous transfers allow guaranteed bandwidth (which is needed for audio/video transfers) but does not provide for error correction or retransmission.
Speeds supported are 100, 200, 400, 800, 1200, 1600, and 3200Mbps. IEEE 1394 devices commonly include the speed as part of their description or name; for example, a FireWire 800 device transfers at speeds up to 800Mbps. With FireWire, as many as 63 devices (using cable lengths up to 14 feet) can be connected (daisy chained). The IEEE 1394 standard supports hot swapping, plug-and-play, and powering of low-power devices.
An IEEE 1394 cable has 4, 6, or 9 pins. A 4-pin cable/connector does not provide power, so the device must have its own power source. The 6- and 9-pin connectors do provide power. A 6-pin connector is used on desktop computers and can provide power to the attached IEEE 1394 device. A 9-pin connector is used to connect to 800Mbps devices that are also known as IEEE 1394b devices. Figure 1.44 shows an IEEE 1394 port found on PCs, a mini port found on mobile devices, and a 9-pin port found on 800Mbps IEEE 1394 devices. Figure 1.45 shows three IEEE 1394 ports on an adapter.
Table 1.4 IEEE 1394 standards Standard | Other names | Description | Cable | IEEE 1394 | S100, S200, S400, and FireWire 400 | Speeds of 100, 200, or 400Mbps half-duplex (one transmission direction at a time); 6-pin connector (later named the Alpha connector)* | ~15 feet (4.5 meters) on a single cable; up to 60 feet (18 meters) with extra cables and a repeater | IEEE 1394a | S100, S200, S400, and FireWire 400 | Added a 4-pin nonpowered connector | See IEEE 1394 | IEEE 1394b | S800, S1600, S3200, and FireWire 800 | Speeds up to 3200Mbps; added a 9-pin (Beta) connector and CAT5e or better UTP (unshielded twisted pair) cable* | ~15 feet (4.5 meters) on a single cable; 330 feet (100 meters) with CAT5e or better or optical cable | IEEE 1394c | S800T | Up to 800Mbps over CAT5e or better UTP cable* | See IEEE 1394b | IEEE 1394d | N/A | Added support for single-mode fiber | N/A | eSATA Ports
SATA (serial AT attachment) is used for connecting storage devices such as hard drives or optical drives. A 7-pin nonpowered eSATA (external SATA) port is used to connect external storage devices to computers at a maximum of approximately 6.6 feet or 2 meters. An eSATA port is commonly found on laptops to provide additional storage. If the internal hard drive has crashed, an external drive connected to an eSATA or USB port could be used to boot and troubleshoot the system.
A variation of the eSATA port is the eSATAp port, which is also known as eSATA/USB or power over eSATA. This variation can accept eSATA or USB cables and provides power when necessary. Figure 1.47 shows a standard eSATA port and an eSATAp (eSATA/USB combination) port
Network Ports
Network ports are used to connect a computer to other computers, including a network server. The most common type of network port is an Ethernet port. A network cable inserts into the Ethernet port to connect the computing device to the wired network. A network port or an adapter that has a network port is commonly called a NIC (network interface card/controller).
Ethernet adapters commonly contain an RJ-45 port that looks like an RJ-11 phone jack, but the RJ-45 connector has 8 conductors instead of 4. UTP (unshielded twisted pair) cable connects to the RJ-45 port so the computing device can be connected to a wired network. AnRJ-45 Ethernet port can also be found on external storage devices. A storage device could be cabled to the wired network in the same fashion as the PC. Figure 1.48 shows an Ethernet NIC with an RJ-45 port.
Modem Ports
A modem connects a computer to a phone line. A modem can be internal or external. An internal modem is an adapter that has one or two RJ-11 connectors. An external modem is a separate device that sits outside the computer and connects to a 9-pin serial port or a USB port. The external modem can also have one or two RJ-11 connectors. The RJ-11 connectors look like typical phone jacks. With two RJ-11 connectors, one can be used for a telephone and the other has a cable that connects to the wall jack. The RJ-11 connector labeled Line is for the connection to the wall jack. The RJ-11 connector labeled Phone is for the connection to the phone. An internal modem with only one RJ-11 connector connects to the wall jack. Figure 1.49 shows an internal modem with two ports.

Docking Stations and Port Replicators
Docking stations and port replicators add connectivity and expansion capability to laptop computers. A docking station allows a laptop computer to be more like a desktop system. A docking station can have connections for a full-size monitor, printer, keyboard, mouse, and printer. In addition, a docking station can have expansion slots or cards and storage bays.
To install a laptop into a docking station, close the laptop and slide the laptop into the docking station. Optionally (depending on the model), secure the laptop with locking tabs. Figure 1.52 shows a docking station and the ports that can be found on a docking station.
The port replicator is similar to a docking station but does not normally include expansion slots or drive storage bays. A port replicator attaches to a laptop and allows more devices to be connected, such as an external monitor, keyboard, mouse, joystick, and printer. To use a port replicator, normally the external devices are connected first. Align the laptop connector with the port replication connector. Attach the port replicator to the laptop. Today, most laptops come with many integrated ports; therefore, docking stations and port replicators are not as popular. Also, port replicators and docking stations are normally proprietary, which means that if you have a particular brand of laptop, you must use the same brand docking station or port replicator.
Being able to identify ports quickly and accurately is a critical skill in computer repair. Table 1.5 lists the most common computer ports.
Table 1.5 Common computing device ports Port | Usage | Port color code | Common connector | PS/2 mouse | Mouse | Green | 6-pin mini-DIN | PS/2 keyboard | Keyboard | Purple | 6-pin mini-DIN | IEEE 1394 | Camcorder, video recorder, camera, printer, optical drive, scanner, speaker, hard drive | Gray | 4-, 6-, or 9-pin IEEE 1394 | USB | Printer, mouse, keyboard, camera, scanner, digitizer, external hard drive, optical drive | Black or blue | USB Type A, Type B, mini-USB, micro-USB | Parallel | Printer, tape backup | Burgundy (dark pink) | 25-pin female D-shell | Serial | External modem, digitizer | Teal or turquoise | 9-pin male D-shell | Video | Analog monitor (VGA or higher) | Blue | 3-row 15-pin female D-shell or mini-VGA port | Video | DVI digital or analog monitor | White | 3-row 18- or 24-pin female DVI, mini-DVI, or micro-DVI | Video | HDMI digital audio and video monitor | N/A | 19 or 29-pin HDMI, mini-HDMI, or micro-HDMI | Video | DisplayPort digital audio and video monitor | N/A | 20-pin DisplayPort or mini-DisplayPort | Video | RGB/component video analog video output | Red, green, and blue | RCA jack | S-Video | Composite video device | Yellow | 7-pin mini-DIN | Audio | Analog audio input | Light pink | 1/8-inch (3.5mm) jack | Audio | Analog line level audio input | Light blue | 1/8-inch (3.5mm) jack | Audio | Analog line level audio output from main stereo signal | Lime green | 1/8-inch (3.5mm) jack | Audio | Analog line level audio for right-to-left speaker | Brown | 1/8-inch (3.5mm) jack | S/PDIF | Audio input/output | Orange | RCA jack (coax) or TOSLINK (fiber) | Game port/MIDI | Joystick or MIDI device | Gold | 15-pin female D-shell | Ethernet | UTP network | N/A | 8-conductor RJ-45 | Modem | Internal modem or phone | N/A | 4-conductor RJ-11 | eSATA | External storage devices | N/A | 7-pin eSATA port | eSATAp | External devices | N/A | Combination eSATA/USB port |
Chapter 4 Disassembly and Power