1. I/O and Multimedia Ports and Devices
A+ Certification
Chapter 7
I/O and Multimedia Ports and Devices

2. Chapter 7 Objectives Understanding I/O Ports.
I/O ports used to send information to and from the processor.
Fix issues with PS/2, LPT, serial, and USB ports.
Understanding Input Devices.
Characteristics of keyboards, mice, and other input devices.
How to take clean/care for keyboards, mice, and so on.
Understand Multimedia Devices.
Webcams, cameras, microphones, and video capture cards.
Installing Input and Multimedia Devices.
Install keyboards, mice, webcams, and so on.
Troubleshooting Input and Multimedia Devices.
How to troubleshoot the input and multimedia devices.
This lesson can be challenging for new technicians trying to absorb how data goes into and out of a computer. Make an effort to illustrate your lesson as much as possible by referring to photos or actual equipment when describing I/O ports and devices. Note: Mr. Soper does an excellent job describing how to implement many of the I/O ports. Having students do the steps as he describes them, concurrently as you explain them, will add depth their understanding and ability to retain the information. It might also be well to explain the difference between I/O addresses and I/O ports.

3. Input/Output Ports Electronic highway to send information to/from:
Processor
Memory
Input ports assigned to devices include:
USB
PS/2 keyboard or mouse
Serial
Firewall
Ethernet network interface
Audio jacks
Other ports:
Legacy and developing standards
Topic 7.1: Instructor Explanation: I/O Ports and Devices
Ask the class:
What good can the processor accomplish if no input is received and no output is delivered to its users?
The answer is zero, nada. You spent good money on a CPU, motherboard, and memory to do absolutely nothing.
The purpose of these lesson topics is to help you understand how we get input to the processor and how the output is channeled into to the right device. For example, you type the letter "A" and suddenly it appears on your computer screen. You have just experienced input and output, but what if it did not appear, or the letter "Z" appeared? You have an I/O problem. The problem could exist in the keyboard, the keyboard controller, the motherboard, the processor, or the video display subsystem. These types of problems are almost endless in their varieties, but they all boil down to getting the data from an input device into the computer and then out of the computer to an output device, such as a monitor, audio channel/speakers, telephone, and so on.

4. I/O Ports

5. USB Connector types: Cable length: Versions:
Series A (to connect to PC or USB hub).
Series B (to connect to printer).
Mini-B connects to digital cameras.
Cable length:
Best is 6 feet or less.
Maximum is 5 meters.
Hubs can be used to extend length.
Versions:
USB 1.1
12 Mbps.
USB 2.0 (also known as Hi-Speed USB)
480 Mbps.
Topic 7.2: Why So Many Connectors?
New students get bewildered looking at all the different physical ports with their connectors and wondering what gets connected to what. A little history will help demystify this. Explain that the initial developers of computers had great plans for how to use cables to deliver a wide array of signals. Imagine, however, what kind of cable would be needed to hold a wire for each key on your keyboard. With 101 keys, the typical keyboard wire would be very thick indeed. So, the developers have found ways to keep the cable size smaller by employing many different and evolving techniques. The evolution has now made it possible to send serial data across that keyboard cable using USB and a comparatively very thin wire does the job very nicely. More recently, wireless keyboards and mouse combinations have made input even more convenient. Just the same, the makers of motherboards cannot just eliminate every port on the back of the motherboard every time some new idea springs up. They must accommodate older software and older devices as well as new ones. As a result, you often see an array of input and output connectors on the board. No matter what you are looking at, you have two important questions to ask:
Is this an input, an output, or both?
Older devices tend to be only inputs OR outputs.
Newer devices tend to accommodate both directions.
For example, a touch screen display is both an input and an output device.
Is this connector compatible with the device I am connecting it to?
This is critical. Most of the time, if it physically fits, it will work, like a video connector. However, there are times when you need to pay some extra attention to ensure maximum compatibility, such as USB 1.1 vs. USB 2.0 devices. Also, some com port devices have different wiring setups.
A final consideration deals with connector conversions. How do you convert a com port to be a USB port or vice versa? How do you convert a DVI connector to a VGA connector?
With this background, we can explore some connector types.

6. USB Connections

7. Adding USB Ports Motherboard connectors for USB cables: Hubs:
Often used to provide front-side USB connectors.
Hubs:
Bus-powered:
100 milliamp limit on bus power to USB devices.
Self-powered:
Uses AC power adapter—500 milliamp limit.
Add-on cards:
PCI slot cards with USB ports attached.
Explaining USB
USB evolved in part because the traditional com port was too slow and cumbersome to deal with. As the need for higher data rate transfer evolved, the need for a better connector with more functions evolved as well. Specifically, a need was expressed for a connector that contained an electrical power wire to light up small devices and provide a way to charge their batteries. Things like PDAs, smartphones, and GPS devices all benefit from this feature. Another feature wanted was the ability of a connected device to be automatically detected, its driver installed, and functionality achieved with minimal response or knowledge on the part of the user.
To keep the right connector connected to the appropriate device, two end connectors were developed. You see them referred to in the book as Series A and Series B. (The instructor should be prepared to hold and pass around a sample USB cable.) You see that the Series A connector is plugged into the case/motherboard. The Series B connector is for a device such as the printer. There is also a version of the Series B called the Mini-B that you see on many cameras and phones.
The main drawback of using USB is the cable length and end connector. USB cables do not employ any special protection against electrical interference. As a result, cable lengths of six feet or less are recommended. You can extend the total length from the computer to the device using a repeater USB hub, but again you can only go six feet from the hub. What happens if you try to extend the length without paying attention to this fact? You are likely to get signal degradation and corruption from other nearby signals such as other USB cables, amplifiers/speakers, telephones, and so on. Because the end connectors stick out an inch or so with the cable coming off of the end and sticking out further, USB can become a tripping hazard on floor tower systems. What happens more often is that someone will bump into a USB memory stick and bend the connector, often making it unusable. Some of the newer tower cases have taken this into account, mounting the USB in its own recessed dock near the top of the computer case, both protecting it as well as making it easier to access while sitting in a chair.
A practical consideration when connecting USB has to do with the nature of the connector design. They did not consult with me on it, so I am not to blame. The Series A side is a rectangle. The connection pins are skewed to prevent accidentally putting the connector in upside down. However, it can be done as one of my students demonstrated, subsequently frying the motherboard. Instruct students to be aware that if the attempt to plug in the connector seems a bit too resistant, they might be about to make a mistake.
One troubleshooting issue that will occasionally pop up with users has to do with putting a USB device on one root hub, pulling it out and putting it in another one. Sometimes the system registration has identified that device with a particular USB root and is stubborn about it. This is especially true if the user did not use the USB device ejection option from the taskbar. The user can do one of two things. The easiest is to plug it back into the original USB port it was in. The other is to log out and log back into the system and let a new USB registration for that root take place.
Topic 7.3: Instructor Explanation: Ports - A Reality Check
There is the exam, and there is real world. What often happens with these exams that the objectives are mapped out over the course of six months to a year. Then books like this are published, so by the time the whole curriculum comes together ready for presentation, devices and software are six months to a year closer to obsolescence. For example, SPDIF optical ports and FireWire ports were a wonderful idea. However, USB caught up with them in terms of functional speed. So, why use ports that you are unfamiliar with if you don't have to? On the newer motherboards, you often see a combo PS/2 port for the keyboard and mouse. Why? It is a simple realization that keyboards and mouse pointers are going to the USB connector standard. Same goes for the old nine pin serial com port. There used to be two of them on every PC. Try to find that feature on a new motherboard now! You now have to use a USB to com port adapter to make that connection. The point is to not get too hung up on the ports and connectors. If you are buying a new PC in 2009/2010, you want as many USB ports as you can reasonably get. But will that be true in 2012? We will not know until we get there.
There is one consideration about USB port sharing to be somewhat aware of. Although the system will handle a theoretical maximum of 127 USB ports, keep in mind that the data throughput is based on the whole USB system. So, all devices on USB are sharing the IRQ subsystem. Most users are not going to use more than a half-dozen USB devices simultaneously, so it is largely a mute issue. However, if you are trying to transfer movies from your USB hard drive at the same time you are using a USB wireless device to download another movie to your 16GB USB memory stick, don't be surprised if the IRQ system complains about being overworked.

8. Small Computer Systems Interface (SCSI)
Industrial grade add-on to support more peripherals:
High-performance drives.
Image scanners.
Backup-drive systems.
File storage systems.
Optical drives.
Two types:
Narrow SCSI:
7 extra devices supported.
Wide SCSI:
15 extra devices supported.
SCSI: Fuzzy Thoughts to Relay
The student manual author really explains SCSI very well and very thoroughly. However, the one thing that a new technician is going to have to do when it comes to SCSI is learn to do research. Most manufacturers of SCSI devices provide detailed instructions on how to make SCSI work on your system and following these instructions right down to the sub-step of the sub-step will ensure a flawless installation with minimal maintenance

9. SCSI Connections: Looks like IDE ribbon cable. Narrow SCSI: Wide SCSI:
50-pin cable.
Three-jumper DIP switch.
Use to set device ID of devices connected to the cable.
Wide SCSI:
68-pin cable.
Four-jumper DIP switch.
Set device ID for up to 15 devices.
Refer to Table 7-2 for device ID jumper settings.
Note: SCSI card manufacturers usually offer very detailed explanations on how to set up SCSI. Careful attention usually solves any problems that might have been encountered.

10. SCSI Chain and Device ID

11. SCSI Termination
Terminators are used to prevent an electrical signal from bouncing back onto the wire after encountering a short.
External devices usually have termination built in.
Other SCSI devices:
Passive terminators:
Use no power.
Not recommended for more than two devices.
Active terminators:
Use a voltage regulator for better termination on SCSI daisy chains.
Consult manufacturer’s website/documentation when in doubt about the type of termination to be used.

12. Serial Ports (Com Port)
Used for:
External modems
Serial mouse or pointing devices, such as trackballs or touchpads
Plotters
Label printers
Serial printers
PDA docking stations
Digital cameras
PC-to-PC connections
Connectors:
DB9M (9-pin)—Male connector.
DB25M (25-pin)—On older systems.

13. Serial Ports (Continued)
Typical modem light indicators from a serial connection:
Carrier Detect (CD)
Receive Data (RD)
Transmit Data (TD)
Data Terminal Ready (DTR)
Signal Ground (SG)
Data Set Ready (DSR)
Request to Send (RTS)
Clear to Send (CTS)
Ring Indicator (RI)
The pins on the connector correspond to one of these functions:
Crossing two end connectors to have the transmit pins connected to receive pins creates a null modem cable.

14. IRQ and I/O Addresses Assigned to Serial Com Ports1 4
3F8 – 3FFh 2 3
2F8 – 2FFh
3E8 – 3EFh
2E8 – 2EFh
Review Table 7-9 Before Taking the A+ Exam.
Hint: Look at the number patterns. IRQ is 4343 as you go from ports 1–4.
I/O address pattern is The hex change is FFEE in the second position.
Remember that there may only be one physical serial port. These com ports are created by assigning memory slots to the IRQs. In this manner, four devices can use a single port.
Topic 7.5: Analogy: Physical Ports and Virtual Ports
You may have had the experience of sending a letter to someone who is staying at some location temporarily. If so, then the explanation of the difference between a physical port and a virtual port should be easy to understand. Suppose that you were staying at one of those hotels with the suites you rent for a week or month at a time. In telling people how to send you mail, you can't just have the mailman deliver it to your room directly. In fact, you may change hotel rooms a couple of times before checking out. So, you tell your contacts to address mail to you with the term "in care of" on the address like this:
Rob Thomas, Guest
In Care of Front Desk
Home Away from Home Hotel
100 Main Street
Anytown, ThisCountry
The physical address is 100 Main Street, and specifically, the Front Desk. As far as the mailman is concerned, Rob lives at the front desk of this hotel. However, the hotel has a record of which room Rob Thomas is in and can call him to come get his mail or (for a small tip), have it delivered to his room, whatever that might be. As a result, no one sending mail will need to know if Rob has changed rooms.
In similar fashion, the motherboard uses an IRQ subsystem for handling USB ports. We call it IRQ steering. For example, there might be only one IRQ assigned to all the USB ports. This IRQ will act as the front desk in directing the flow of data to the devices connected to the various USB connectors. However, not all USB devices get the same priority. Through a process called enumeration, if a device is receiving streaming data such as a sound system, it gets higher priority than non-streaming data, such as a keyboard or printer. With USB 2.0's 480Mbps capacity, the data demand of the individual USB devices is not likely to be an issue. However, as more video-intensive transfers occur, this could change.

15. Serial Port Configuration
Common settings that must be examined for successful use:
Transmission speed:
From as low as 300 bps to as high as 115,200 bps.
Faster on newest UART chips.
Different word lengths:
7-bit or 8-bit.
Different methods of flow control:
XON/XOFF or DTR/DSR.
Different methods of ensuring reliable data transmission:
Even parity, odd parity, no parity, 1-bit, or 2-bit parity length.

16. Parallel Ports Address LPT Port # LPT1 7 378-37Fh or 3BC-38Fh LPT2 5
25-pin female connector.
Traditionally used for printers.
Found mostly on older systems.
LPT Port #
Address
LPT1 7
378-37Fh or 3BC-38Fh
LPT2 5
278-27Fh or Fh
LPT3
278-27Fh

17. IEEE 1394 (FireWire) High-speed serial transmission. Used for:
Digital cameras
Video cameras
1394a—FireWire 400
400Mbps
1394b—FireWire 800
800Mbps
Like USB, devices are hot swappable.

18. Other Common Ports PS/2:
Used for legacy motherboard connections to keyboard/mouse.
Centronics printer ports:
36-pin cable.
Audio mini-jack:
1/8-inch size.
PC99 color coding
Pink – Microphone.
Light Blue – Line in.
Lime Green – Stereo/headphone connection.
Brown – Left to right speaker.
Orange – Subwoofer.
SPDIF digital audio:
Fiber-optic cable connection for audio devices.
MIDI – Musical Instrument Digital Interface.
Topic 7.4: Instructor Explanation: On-Board vs. Peripheral Card
One of the more difficult decisions to make when purchasing or building a new PC has to do with whether to use on board ports or buy dedicated cards for the same functions. Three areas of concern typically surface here:
Board Audio Ports vs. Sound Cards
On-board Video vs. Graphics Cards
On-board HDMI vs. Graphics Card HDMI
In each of these three cases, the answer will involve the following:
Assessing what it is that you plan to do as a PC user
Researching the chip set of the motherboard you are purchasing
Real-time assessment of the quality of the result
Comments:
Audio Output: Early versions of motherboards admittedly had some pretty poor sound chips. Newer motherboards have, in some cases, gone to the sound card manufacturers and paid a royalty for the right to use their sound chip and software to create a very acceptable experience. Recommendation: After you have think you have settled on a motherboard choice, research the sound chipset. It might do everything you need it to do. If not, you can always add a sound card.
Video Output: Most business/office applications can work pretty well with the onboard video. However, once you cross the line into multimedia, the choice to add a graphics card is pretty easy. The question then becomes which one, which is covered later in this book. Note: Hard-core gamers like to brag about their $600 graphics card and if it is being used to enhance game play that is one thing. However, if your definition of multimedia is watching TV/DVD, $550 will buy you a 42" HDTV, which will do the job much better with much better effect.
HDMI: The same reasoning applies to having onboard HDMI as video. This is a relatively new feature and is very popular on the new Home Media Server types of systems. Because it is new, the quality is still being tweaked. If I were actually planning to use my computer to play back hi-def movies, I would likely opt to get a second graphics card with HDMI output. If it is being used to display family photographs on your 52" LCD, you may find that the onboard HDMI port is quite adequate.

19. Input Devices Keyboard: Typically USB, but PS/2 on older devices.
Needs to be installed before boot or error messages are generated.
Mouse:
Again USB, PS/2 on older motherboards.
Watch for resource conflicts (IRQ) on older devices.
Bar Code Reader:
Used in retail businesses.
Biometric:
Fingerprint reader/retinal scanner.
Touch Screens
Becoming very common on small screens:
GPS, PDA, some small notebook PCs.

20. Mouse Properties Tabs

21. Multimedia Devices Webcam: Generally USB or plug ‘n’ play.
Digital camera:
Generally USB or PnP; uses camera wizard.
MIDI music/MIDI ports:
Install with system off; restart; install drivers.
Sound cards:
Install into PCI slot; PnP will discover it.
May need to provide driver disk and update drivers from manufacturer’s website.
Legacy sound cards often cause IRQ conflicts.

22. Multimedia Devices Microphone: PnP; will have to adjust settings.
Video capture card:
Install as per usual instructions into PCI/PCIe slot.
Restart system.
Provide drivers/update as needed.
Connect cables to source devices.
Set up video capture software.

23. Troubleshooting Input/Multimedia
Keyboards:
Damaged keyboard connectors/cable.
Check for dirt or sticky keys.
Caution: Plug keyboards into PS/2 ports with system off.
Use “substitute known good for suspected bad principle:”
Verifies that the bad keyboard is indeed bad.
Mouse and other pointing devices:
Check for damage connector/cable.
Learn to use the Mouse Properties (control panel).
Clean the mouse track ball of lint or grease.
Reinstall the mouse driver software.
Check for hardware conflicts.

24. Troubleshooting Input/Multimedia
Touch screen inputs:
Software problems/bad drivers.
Use any diagnostic software provided by vendor.
Video alignment problems.
Touching screen results in incorrect movements.
Re-align video using the vendor utilities.
Hardware issues.
Defective screen due to shorts or bad power supply.
Replace or repair as directed by manufacturer.
Sound cards:
Conflicts with onboard sound cards.
Disable onboard sound card in BIOS.
Poor performance.
Recheck software driver version; check mixer controls.

25. Troubleshooting USB System
When USB ports do not work:
Check to see if USB port is enabled in BIOS.
Check on USB versions (1.1 or 2.0) for use with devices.
Check for device driver updates.
Check for power problems on bus-powered hubs:
Some devices use more power than the 100 milliamps provided.
Slow performance:
Too many devices using the available 12Mbps on USB 1.1.
Determine if a USB 2.0 port is running in 1.1 mode.

26. USB Power Problem

27. Troubleshooting Com/Serial Ports
Check physical connection:
Mismatched connectors.
Receive/transmit pins must be set properly.
Check IRQ settings for resource conflicts.
Serial port dropping characters?
Check UART chip for latest version.
Adjust settings:
Device Manager  Ports.
Serial Communications  Port Settings, Advanced.
Adjust receive buffer or send buffer.

28. What Have You Learned?
List three things that you did not know before this presentation.

29. Exercise
Scenario:
Your system was running fine, but you occasionally notice that the sound output is "glitchy" and you decide to add a sound card. As luck would have it, a friend gave you his old sound card from a system he is throwing away. You install it, and the sound is great; however, whenever you try to download your songs at the same time you are playing them, either the download or the play stops or is intermittent. It seems worse than it was before you added the sound card. What would you do to troubleshoot this?

30. Chapter 6 Summary Understand I/O Ports.
I/O ports used to send information to and from the processor.
Fix issues with PS/2, LPT, serial, and USB ports.
Understand Input Devices.
Characteristics of keyboards, mice, and other input devices.
How to take clean/care for keyboards, mice, and so on.
Understand Multimedia Devices.
Webcams, cameras, microphones, and video capture cards.
Installing Input and Multimedia Devices.
Install keyboards, mice, webcams, and so on.
Troubleshoot Input and Multimedia Devices.
Troubleshoot the input and multimedia devices.