Working with Peripheral Devices

This is a guide on working with peripheral devices.

Printers

Now we'll talk about that process in greater detail in a moment. But most laser printers these days are for both monochrome and color printing as well as what's known as duplex printing or printing of both sides of the paper. [Video description begins] It's also known as dual-sided printing. [Video description ends] And like most technologies, the price has only declined over the years. Early model laser printers were very expensive compared to other types. But these days, it's not at all uncommon to find laser printers in small businesses or even at home. And when it comes to laser printers, it's really tough to beat their quality and speed. And the two main values you would want to pay attention to if you're shopping for one would be the DPI, or Dots per Inch, and PPM, or Pages per Minute.

Now the DPI would be the quality, and that might compare to the resolution of your screen, for example. The more pixels you have the better the image, so likewise the more dots you have the better the image. And PPM is just as it sounds, it's the number of printed pages that can be produced per minute. Now you'll likely see quite a variance here for both values depending on the make and model. But for even a small business or a home model, I wouldn't be surprised to see a DPI value of around 600 to 1200, and maybe a PPM value of around 10 to 15. But higher-end models in the workplace could offer significantly higher values for both, but of course they would be much more expensive as well.

So then, looking at the process, it uses these steps in sequence for every job, beginning with processing, whereby the digitized image is prepared to be transferred to a photosensitive drum. Now that's a rotating cylinder that responds to light, hence this is where the laser comes into play. Then charging uses what's known as a corona wire to apply a uniform negative 600 volt charge to the drum, which repulses all toner away from the drum. During exposure, a laser beam is then focused on the drum, which discharges any areas of exposure, effectively draining the charge off the drum. And all points exposed to the laser will now attract the toner.

Development occurs because of the difference in electrical charge. The toner is now attracted to the areas discharged by the laser, and still repulsed by areas where the charge remains. And then transferring involves another corona wire that carries a positive charge, which is positioned permanently beneath the paper and draws the negatively charged toner from the drum onto the paper. And fusing uses a heated roller to literally melt the toner into the final image and press it, if you will, into place.

And finally, cleaning and recharging involves a wiper blade to remove any toner from the drum, and any remaining static voltage on the paper is also dissipated. And the drum is also exposed to what's known as an erase lamp, which returns it to a neutral charge, essentially just setting everything up for the next job.

Now much more common in the home environment is the inkjet printer, which uses ink cartridges and printheads that move across the page with a focused spray of ink to produce the image. Now there are two primary methods of doing this: continuous inkjet and drop-on-demand. Continuous would likely be more common in manufacturing or producing labels for products with fairly high quality, while drop-on-demand would generally be more common for home printing. But one of the main considerations for inkjet printers in either case is what's known as the printing heads.

A fixed head means that the print head itself is a component of the printer and it's designed to last for the lifespan of the printer, while a disposable head is a component of the ink cartridge and is replaced every time you change the cartridge. With a fixed head, the ink cartridges are little more than just containers, and they can often be a little less expensive to replace or refill. But if the print heads themselves become clogged or damaged, you pretty much have to replace the whole printer. Whereas with disposable you'll get new print heads with every new cartridge. But the cartridges themselves tend to be more expensive to the point where in some cases, if you were to buy a new high capacity black and a high capacity color cartridge those two themselves, in some cases, could cost as much as the printer itself if it's a lower-end model.

Now the next type is the dot matrix printer, and these work on an impact principle, whereby pins strike an ink-soaked ribbon onto the paper behind it and this is effectively the way that typewriters work. Now they've been largely replaced by inkjets, but they do still have some current applications, maybe at a point-of-sale register or a cash register or maybe even an ATM, an automated teller machine, but they tend to remain in use because of its ability to produce multiple copies simultaneously. Many invoices, of course, will have one copy for the customer and one for the vendor, so a dot matrix printer can produce both copies at the same time.

And finally, thermal printing, which relies on heating thermal paper. So the paper itself is actually treated and as you heat it, it turns black where you want the image to appear. They're typically smaller and faster than dot-matrix, so they're ideal for portable devices. And the common applications might still include a point-of-sale, maybe label printing, or maybe even at a gas station the receipt that comes out might use a thermal printer. [Video description begins] It is used on gas station pumps. [Video description ends] And as mentioned, when you heat the paper, it effectively turns black, but you might even see some color, but usually only one other one. And what happens here is it uses two different temperatures; one to produce black and the other to produce the color. But because they are quite small, they are very good for mobile applications.

Flatbed and Barcode Scanners

Now there are two main methods of accomplishing this, what's known as CCD or Charged Coupled Device scanning, where this actually uses a lens to reduce the image. So for all intents and purposes, it takes a picture of whatever you are scanning. And this typically can result in a higher quality, but is more commonly used for large format scanning. The type of scanning you might find in an architectural firm or maybe engineering, something along those lines. And the other option is the CIS or Contact Image Sensor scanner, where this uses a moving set of three red, green and blue LEDs to measure, again, the intensity of each of those colors. And this typically is what you would find maybe in a home environment because it is generally a lower cost and a more compact format. [Video description begins] The acronym for red, green, and blue is RGB and the acronym LEDs stands for light emitting diodes. [Video description ends]

As for the connections, you certainly can find a network connection, again, probably a little more common in the larger format. So again, that architectural or engineering environment might have a fairly large scanner and this certainly could just operate over the network. But if it's a local connection, you still might find a SCSI interface, but that would probably be an older device. And even older still, maybe even a parallel port. That was the old type of printer connection prior to USB. [Video description begins] The acronym SCSI stands for Small Computer System Interface. [Video description ends] And you certainly might find FireWire still out there, but I would say, overwhelmingly for local connections, you would find USB. [Video description begins] The acronym USB stands for Universal Serial Bus. [Video description ends]

Now the barcode scanners are similar in terms of the operation to a flatbed scanner because it's still just using a light source, and in many cases, a lens and a sensor, of course, to just interpret an image. But with a barcode, it really is just converting the light impulses to electric signals by decoding the pattern of black and white bars. So we're not really concerned with producing, or I guess I should say, reproducing any kind of image here. We just want to read something. So every barcode, of course, has a unique signature with respect to that pattern of black and white bars. And the scanner can just pick up on that and convert the black and the white to ones and zeros.

So some of the key features of barcode scanners include the light source itself. And you might often find an LED scanner, but perhaps more commonly, a laser scanner. And both of those do tend to have to be fairly straight on to the barcode to get a good reading. So in some cases, you might find an omni-directional barcode scanner, where it uses what's known as a starburst pattern. It uses a combination of straight lines and angled lines to better read the barcode if it's on an angle. You might see these recently in airports when it's trying to read your bag tag. It moves around, and it has a variety of different directions to try to pick it up regardless of whether it's face on or not. And it's not uncommon these days to find smartphone-based scanners that typically are built into the camera. But you can just essentially direct the scanner onto a barcode and it can interpret the information from that code.

Now with respect to the barcode scanner connections, again, they may be using the network depending on the type of scanner. Again, maybe that luggage scanner in the airport certainly would have some kind of network connection. But mobile devices tend to actually use WiFi or even cellular. For example, shippers, when they deliver a package, they might scan it when it's been acknowledged. And that might actually use cellular to transmit that information back to the headquarters, if you will. But again, if it's a locally connected device, most commonly, you would find a USB connection.

Monitors

Now this is what most of us would likely consider to be the old-style monitor. For the size of the screen, the entire unit itself is very large, very bulky, quite heavy, and it took up a lot of desk space. So you don't tend to see very many CRT monitors left in use these days. But the idea behind it is that the Cathode Ray Tube, essentially refers to the negatively charged aspect of the tube. This was effectively a heated filament in a vacuum sealed glass tube that fired out electrons. And the screen was phosphor-coated, which meant it was photosensitive essentially. And it contains millions of tiny red, green, and blue dots, and they would glow when struck by the electron beam. So they were able to reproduce the colors, of course, that we see on the screen. But again, the main drawback of the CRT monitor was its size, its weight, and its bulkiness.

So more commonly these days, we tend to find the liquid crystal display, which implements LED backlighting. And this, of course, is what you will invariably find on a laptop because of course, it just has a flat screen. It also has much lower power consumption compared to a CRT. It's very lightweight and can be made in a very compact small size. So obviously ideal for laptops. But these have also replaced the CRT technology for desktops. Again, almost every system these days will likely be using some kind of LCD display. And it's also ideal for today's high definition content.

Now with respect to the characteristics of an LCD monitor, you do want to pay attention, of course, to its maximum screen resolution. Now this is also going to be a function of your computer itself with respect to the video card that you have. You don't just always want to go for the maximum resolution if your video card can't produce that resolution. So just be mindful of both. But overall the resolution is quite simply the number of pixels on both the horizontal and the vertical. And the aspect ratio refers to the ratio between those.

Now typical ratios these days tend to include four to three, so for every four pixels on the horizontal there would be three on the vertical. And this of course creates a rectangular image that we tend to find on most LCD screens. But more recently you would probably find ratios of 16 to 9, or 16 to 10. Now, again, this depends on the physical shape and size of the screen itself, but those are common ratios.

The display size is the overall size of the screen, but it is measured with just a single value that is measured from diagonal corner to diagonal corner. So it's not the length or the width. It would be, for example, the top-left corner to the bottom-right. And typically, you would see values, again, maybe 13 inch, 15 inch, or 17 inch for laptops. But, of course, for a desktop monitor it can be much larger.

And the response time is certainly something that you will want to be mindful of, particularly if you are gaming or needing to do very high-end graphics design. Generally the gamers need to see the screen refreshing as quickly as possible. But the response time is not quite the same as the refresh rate. The response time refers to the amount of time it takes a pixel to go from black to white and back again, or white to black and back again. And it's typically measured in milliseconds. Now for a gaming type of system, you would want to see at least four milliseconds or better, maybe even as low as one. But for a standard office type environment, you wouldn't really need anything that fast.

As for some common features of the LCD monitors, some of them tend to have a touch screen built in, again, many laptops feature that these days. But even standard desktop screens may also offer this, so you can quite literally just tap the screen, just like a tablet or a phone. There are usually glossy screens versus very flat ones, and this depends on what type of output you really want to see. For just looking at pictures, for example, glossy tends to be a little more crisp, but for documents then, you generally want to see a more flat type of image.

Some of them do have curved screens, as well. So if you have a very large monitor, for example, then it can tend to get somewhat distorted as you look at the edges from your position. Whereas the curved screen of course, points more toward your eyes from any direction. So those are certainly a little more common these days.

The wide screens are quite simply exactly that. They're a little wider, so the aspect ratio tends to be a little different. And this is typically what you might find if you are just watching movies, they tend to be a little wider. And directional screens tend to try to compensate if you are looking at it from an angle. Early LCD screens did suffer from this. It was fine if you were looking at it straight on, but if you stood on an angle, then you generally saw significant color distortion.

And also be mindful of any other accessories that might be included. Now this refers to things like the connections, for example, you might have a USB connection so that you can connect the monitor to your computer via USB. But that's not for the display itself. That's there so that you can plug other devices that use USB into the monitor. So essentially your monitor just turns into a USB hub. The signal is typically still carried over something like an HDMI connection, but the USB again allows you to just use it as a hub. And integrated components may also be included, such as a webcam or maybe speakers for audio. And then there may be additional connections for the audio, such as a headphone input.

So it's all a matter of what you feel you need in terms of those accessories. Some of them don't have any, but it's always good to know what you might find useful. And of course, then you might end up paying a little more for the ones that have these integrated components. But if you feel that they're worth it, then they certainly do make things a little more convenient.

Virtual Reality

Now in this presentation, we'll take a look at a relatively new peripheral device, that being the virtual reality, or VR headset. And this creates a computer-generated simulated environment that typically implements separate imaging for each eye, so that you get a force stereoscopic and three-dimensional experience along with surround sound to enhance that experience.

And this certainly isn't anything that's particularly common yet, but in the home environment its key application tends to just be for computer gaming. But in a corporate environment, you would probably still find these being used in situations where you need simulations and training, such as flight simulators. Or perhaps even if you are designing architectural plans, and you need to visualize what that plan would look like in three dimensions. Medical applications are using them as well, so they certainly are becoming a little more common as the prices come down.

Now there are typically some other peripherals that go along with VR systems, including head motion tracking and body motion tracking, and even eye tracking within the headset itself. And the head motion tracking, of course, adjusts as you turn your head left and right, it picks up on that and adjusts the surroundings so that it seems that you are, of course, looking left or right or up and down. And the body motion tracking quite literally tracks as you move. So if you're walking through an environment, for example, everything will update accordingly. And the eye tracking is just quite literally what you are looking at, so it can actually determine where you eye focus is and that can be adjusted accordingly as well.

Now in many cases, game controllers will include these types of trackers. For example, game consoles, they will generally have some kind of device that attaches to the controller that picks up on these movements. But they might not be as sensitive as more robust implementations. For example, you can have multiple trackers mounted in a room for a full three-dimensional type of tracking experience. So that no matter which way you move, whether it's forward or backward, left or right, or even up and down, all of this is picked up on much more accurately and can be reflected as such. So, again, in the most robust implementations you'll see multiple detectors mounted on the walls and on the ceiling. And, again, the more accurate the detection, the more accurate the experience.

Optical Drives

Now in terms of functionality, the drive itself is absolutely no different than an internal disc drive. So whether it's CD-ROM, DVD, or Blu-ray, it's the exact same functionality. But these days, one common scenario is if you have a laptop, then one of the most attractive features of laptops these days is how small and how light it is. And as such you will often find that there is no internal optical disc drive in a laptop that wants to be small and light. In fact, the laptop I'm using right now does not have an optical disc drive. So if you find yourself needing one, this is where you'll most likely find one, it is quite literally external. So typically, you'll find these attached with a USB interface.

Now overall this is a relative term, of course, but the device is about the size of a paperback book. Now I realize that's a relative term, but it really doesn't need to be all that much larger than the disc itself. You can see the tray opening there and the disc being inserted. So it's just slightly wider, slightly longer, and maybe slightly thicker than, of course, a disc is itself. So a small paperback book would be a good analogy. [Video description begins] An image of an open external optical disc drive displays. There is a disc in the tray and the disc drive is just slightly larger than the disc itself. [Video description ends]

And there's typically an open and close button right on the drive bay door. So you just press that button and the tray slides out. Your discs are fed into the drive; it operates with a laser, exactly like an internal drive does. Again, functionality-wise, there's no difference. But as mentioned, they're just a little less commonly used because most desktop systems would probably still have an internal drive. But again, these days laptops are favoring the small size and the lightweight aspect. So they simply do not include them in most laptops these days. And, again, it's just far less common that you need them anyway. Again, my personal laptop here does not have an optical drive at all. And I've been using this laptop for about a year and a half now and I haven't found myself needing an optical drive in that entire time because, of course, everything is so readily available digitally these days.

Now as for the uses, again, the functionality does not change just because it's an external device. So this is still used for reading and writing on optical discs, so they typically aren't just readers, you can usually burn as well. And they typically support CDs, DVDs, and Blu-ray discs depending, of course, on which platform you want to use. And typically, you'll find these used maybe for storing large amounts of data, for archival purposes, or just to have back-ups of your personal data, really, whatever you want.

But again, in terms of the functionality, there's no difference just because it's external, it just makes it portable. It makes it something that you can just attach when you need it and leave it detached most of the time. So in that regard, it certainly enhances the functionality of the system, but it's not something that you need all the time. So, again, with the laptop, it can still be nice and small and lightweight. And then when you need the drive, simply attach it, use it, and then put it away.

Mice and Keyboards

Now in this presentation, we'll take a look at perhaps the two most common peripheral input devices: the mouse and the keyboard.

And beginning with the mouse, this does still remain the most effective way to interact with your computer, of course, due to its point and click nature. And, of course, newer mice also have a scroll wheel so that you can scroll through content much more easily.

And in terms of the connections, there have been quite a few. And if we go back to around the late 1990s, early 2000s, the most common connection then was known as PS/2. And this was a cylindrical connector that was barely a centimeter in diameter, probably smaller than your pinky finger. And, in fact, the keyboard used the same connection, but they were usually color coded so you got the right one in the right place. But that was largely superseded by USB, if you're still talking about a wired connection. But, of course, very common these days is the wireless mouse, whereby you simply have a USB receiver and the mouse transmits, usually using Bluetooth, to the receiver.

Now original mice had a little ball underneath and that ball would roll along two axes. One that represented your left and right and one that represented your up and down, and the ball could roll both of them at the same time. So that, of course, gave you your X and Y position on the screen. But most newer mice these days are optical. There's a little light that shines down from the bottom, which removes those moving parts. So they're a little more durable in that regard. That old ball type of mouse was a little bit susceptible to damage because it would pick up dust and dirt from the mouse pad and it could essentially clog up the rollers inside.

But this does require the appropriate surface. For example, you can't use an optical mouse on a glass top table, it will just shine right through the glass. So it needs to be reflective enough so that it can be picked up. But as long as you have a mouse pad underneath, then that's usually sufficient.

And, of course, the keyboard is the most effective way to enter data into the computer. There certainly is no replacement that is nearly as reliable. When it comes to entering data, of course, voice recognition is certainly becoming more common, but I don't think you'll see the keyboard go away for quite some time yet.

And, again, we have the same connections here. If you go back to, again, the late 1990s, early 2000s, most of the time it was a wired PS/2 connection. And, again, that was superseded by USB if it's wired. But there are also wireless keyboards, and typically they come in a set. So if you buy a wireless set you get the keyboard, the mouse, and then just a single receiver which can receive both. Now there are, of course, distance limitations and obstacle limitations. So you would want the keyboard fairly close to the receiver but, obviously, in a desktop computing environment that's usually not an issue.

And in many cases keyboards will also have extra features built in to interact with your computer, now that may require a little bit of software to be installed. It depends on the make and model and, of course, the operating system that you're running. But they usually have features to interact with your audio, for example, so you can increase or decrease the volume. If you're listening to a CD or music you can usually skip to the next track or rewind or fast forward. They might have options to interact with your monitor, so brightness controls, things like that. They might have preset programmable keys that can launch your email program or go to your preferred homepage on the Internet.

So, again, it depends on the make and model, but many keyboards do have those additional features. But, again, usually it's just a matter of installing a little bit of software so that you can configure those keys to perform the tasks that you want them to perform.

Touchpads and Signature Pads

In this presentation, we'll take a look at touchpads and signature pads. And beginning with the touchpad, this is essentially used in place of a mouse. And is typically operated with just your fingertips. And almost always found on laptop systems, so that you can operate with just the laptop all by itself. Because, of course, every laptop has an integrated keyboard. And while you certainly can use a standard mouse with a laptop, sometimes you just want to pick it up and go, and just use the touchpad in place of the mouse.

So it's typically integrated right onto the surface of the device itself, and generally does not take up much space. You can see by the picture that it only is about maybe two to three inches long by about two inches high. And it might seem like the laptop has to be a lot deeper from front to back because of the touchpad, but, of course, the motherboard underneath is occupying much of that space anyway. [Video description begins] A laptop displays. [Video description ends]

Now you can get external touchpads that will connect using either USB or maybe a Bluetooth connection, so that you can quite literally just attach it to any type of computer. Maybe you prefer in some applications to use a touchpad, but something like a desktop computer, for example, would not have one. So you can get them as external devices if desired.

Now the signature pad is similar, but it's not really used for input for a computer or a laptop. It's basically just used to collect an individual's signature. And it's effectively linked then to other data, such as their name, a bar code, a photo or anything else. But it basically just equates that signature to some other type of information.

And the screen itself typically has a backlit LCD, so you can view the electronic writing itself. And you might also be able to navigate between screens. So if, for example, you have to initial each page of a document, then you can put your initial on page one, then swipe to page two, initial there, and swipe to page three and just continue that way.

And in terms of the common applications, it's typically for enhanced security, maybe some kind of legal agreement, or some kind of financial transaction. Perhaps you've had a package delivered to your house and the courier requires a signature. In many cases, that is just a digital signature using a signature pad. But in any application it really just equates your normal signature in digital form to some other type of data.

Game Controllers

Now characters or various objects can be controlled with the game controller. And they'll typically connect to the computer with a USB connection although, again, wireless connections certainly aren't unheard of.

Now earlier versions of game controllers were typically very simple, usually little more than a joystick with maybe a button. But as games have advanced, so have the controllers. So you typically see multi-function controllers now. And often, they will require a device driver to operate on the computer. It is still a peripheral input device. So in many cases, you do need to install a driver so that it can interact with the appropriate operating system.

Now there are other types of game controllers. And quite literally, your standard keyboard and mouse can certainly be considered to be game controllers if you are using them to play a game. Again, a lot of gaming laptops just use the inherent keyboard and mouse for their input. Now that doesn't mean you still can't install an external controller. But it's just that the game typically would allow the keyboard and/or the mouse to be used as input. So in that regard, they are also game controllers.

Now generally, the joystick or the gamepad tends to be a little more common in terms of what you would see with modern games, but you might also find steering wheels for driving games or even light guns for any type of shooting-based game. So there are a number of different types of controllers that are available. And ultimately, it does come down to the type of game that you want to install.

Cameras and Webcams

Now in this video, we'll take a look at digital cameras and webcams as input devices for our computers. And when it comes to the highest quality imaging, you certainly still would want to go with the digital camera.

Most of us, I'm sure, are very familiar with using our phones as our primary camera, but they really don't support the imaging capabilities of a real digital camera. And, of course, someone who is a professional photographer, for example, would never rely on a phone. And most digital cameras these days also support high quality video and audio.

Now when it comes to making this an input device for your computer, this involves, of course, connecting it to your computer. And chances are, if it's a desktop computer, this is probably done with a USB connection. Almost every digital camera would have a USB output and then you just connect it to your computer. But if you have a laptop or maybe even a printer that has a reader, then chances are you'd have a memory card reader built in.

Now your desktop might have a card reader as well. But most laptops tend to have them by default and many printers have them as well. But, again, every digital camera has that memory card that is removable. And then you can just pop that out and insert it into your computer. And many newer cameras would also support wireless networking. So you can just connect it via WiFi and transfer your photos that way.

Now webcams, of course, allow you to engage in interactive communication. So we can have face-to-face communications as opposed to just e-mail or a phone call. And this can allow for more influential conversation. And possibly reduce the risk of misunderstanding as well, because quite literally, they can see the expression on your face. And it's also a little bit easier for group communication. And they can also be used to record content. It's not necessarily just for a video call, for example.

And these days, they are very low cost and convenient. If it's an external webcam, they can usually be placed anywhere on a desk, or in many cases, they can even hang over the edge of your monitor. And if you have a laptop, then it's very likely that you actually have the webcam integrated into the laptop. And there are many monitors that would have them integrated into the device itself as well. But one way or another, as long as you have some kind of webcam, then you can take advantage of all this enhanced type of communication.

Microphone and Speakers

Now a microphone simply converts sound waves to electric signals. So using my voice as an example, as I'm speaking right now, I'm producing sound waves. And the microphone has a small metal foil diaphragm inside of it that vibrates in response to those sound waves. And those vibrations are converted to the electric signals. And of course, this allows us to implement real-time communications, such as voice conversations or video conferencing, or of course, recording.

Now you can get an external microphone for just about any system. Most desktop computers, for example, would not have a microphone included. But almost every laptop these days would have a microphone integrated right into it, although it wouldn't be a particularly high-quality microphone. And if it's an analog connection, then this typically uses what's known as a tip/ring/sleeve connector.

Now this looks exactly like a headphone jack. But you might see two sizes: a larger one, which is also known as a quarter inch jack, and a smaller one, which does look exactly like a headphone connector. But the tip/ring/sleeve refers to its configuration. There is a small rounded tip, then it's slightly indented a little bit below that, that's the ring, and then the rest of the cylinder is the sleeve. But more commonly these days, you would probably find a digital connection, which simply uses a USB connector.

And then on the output side, of course, we have speakers. And speakers are quite literally just the opposite of a microphone. It converts those electric signals that were received by the microphone back to audio. So it still has that same kind of diaphragm in the speaker, but it's much larger and the signal is amplified so we can hear it at an appropriate volume. But really, it's just the direction of the signal that's different, if you will. But this, of course, allows us to hear what was recorded or what is being transmitted, so we can consume that audio content.

And, again, laptops typically tend to have integrated speakers, but again, they usually aren't particularly high quality. So you can get external speakers for any type of system. And they would typically have either a USB connection. Or that 3.5 millimeter mini jack connection, which is essentially the eight-inch headphone jack. Or very common these days, the Bluetooth connection, whereby you don't need any wires at all. You just pair the Bluetooth speaker with the computer or whatever transmitting device you have and, of course, the signal is transmitted wirelessly. And those, of course, are very convenient if you need to place them a little bit farther away from your system than what a cable might accommodate.

Projectors

In this video, we'll talk about projectors, which of course can be used to project images and video, typically onto a wall or a screen. But whatever you are projecting onto should ideally be as flat as possible and even slightly colored.

Now if it's white, that's fine, but if the image you're projecting is predominantly white and then you're projecting it onto a white surface, it can be a little bit hard on the eyes, a little bit too bright. So a lightly colored surface would be a little bit better. And if you look at a screen, they tend to be somewhat silvery or slightly gray in color, just to, again, soften some of those bright colors.

But with respect to the devices themselves, these days there's quite a variety in terms of the size. You can find models that quite literally fit in the palm of your hand if you're traveling a lot. And in contrast, if you went into a very large lecture hall of a university, for example, you'd probably find a ceiling mounted unit that would be much, much larger. And in the graphic here you're seeing a fairly standard desktop size. Still quite portable, good for delivering presentations in boardrooms or maybe classrooms.

So as for the common applications, as mentioned, delivering presentations, so a PowerPoint slideshow or, really, anything else that you need to give to a reasonably small audience, in most cases, for the size of projector that we just saw would certainly be fine. But they're also very commonly used in home entertainment systems these days because, of course, you can get a much larger image. The farther the projector is from the projection surface, the larger the image is. So you can usually get much larger than what you might get on your TV. And if you just need to do demonstrations. So if, for example, I'm delivering a class and my students need to see what I'm doing on my screen, then I just connect my computer to the projector and project that onto the projection surface and, of course, they can all see what I'm doing.

Now one primary factor when it comes to shopping for a projector is the brightness. And the value that you'll find for this is called lumens. And this is quite literally the amount of light output, so in other words, how bright it is. Now that might sound similar to wattage. If you think about a regular light bulb, for example, a 100-watt bulb is certainly going to be much brighter than a 25-watt bulb. But ultimately, wattage is just how much power is being consumed, not necessarily how bright it is. So lumens are exactly that, it is quite simply how bright is the output.

Now this is certainly going to depend on the amount of ambient light that you have to compete with in terms of how many lumens you should have. So again, if you are in something like a fairly small boardroom and you can turn all the lights off, then you wouldn't need a very high lumen value. People would be able to see it very easily. But if it was a larger classroom and you were maybe a farther distance from the wall and the lights needed to be on, so that students could see their textbooks and what not, then, of course, you would need a much higher lumen value.

So you'll see quite a range there as well, maybe between 1500 all the way up to 30000. [Video description begins] The abbreviation for lumens is lm. [Video description ends] Now for the desktop unit that we just saw, I would say that something around 3000 would probably be more than adequate, again, for boardrooms or smaller classrooms. But if we're talking about the large university auditorium, then in most cases you'll need a much higher lumen value. And not just because of the level of ambient light, but of course, the distance that you have to travel. So those much larger units would certainly have a much higher lumen value. But again, for the desktop implementation, usually around 3000 would be fine.

And some of them will have different brightness modes as well, just sort of presets, whereby it can take into account the amount of ambient light and/or the size of the room. So you can just try different modes to see what works better, but that will depend on the make and/or model.

External Storage Drives

In this presentation, we'll take a look at implementing several methods of external storage, beginning with external hard disk drives. And these come in two main varieties: the desktop external hard drive, which houses a 3.5 inch drive; and the portable external drive, which houses a 2.5 inch drive. Now that's essentially the hard drive that you would find in a laptop, so it's physically smaller and as such a little more portable.

Now ultimately both of them are portable because they are external. But the desktop external hard drive, with that larger drive tends to require its own separate power and, of course, a physically larger case. So it is still portable, but not as conveniently as the portable hard drive. The 2.5 inch implementations usually can get by with the power that it draws from the computer itself over the USB connection. So in other words, there's usually not a separate power supply.

Now both of them have high capacity and that's a feature of the drive itself. And they typically use standard connections, such as USB 2.0, USB 3.0, or eSATA. [Video description begins] The acronym for external serial ATA is eSATA. [Video description ends] And it's simply very good for mass storage and archiving. If you just don't want to take up disk space on your internal storage, this is a very good option. And, again, it can be disconnected and taken to another computer very easily. And they're both relatively cheap and reliable.

Now, becoming more common these days is the external solid state drive. And data is stored in non-volatile memory with a solid state drive, meaning that it does not require power to retain its data. So as such, there's no mechanical or moving parts. And this results in several benefits, including lower power consumption while still giving you a very reliable and robust storage mechanism. And it operates much faster than hard disk drives do, because there is no spinning disk, there's no moving parts whatsoever. And this also translates into better reliability, there's simply fewer components that can fail, because again, there are no moving parts.

They still have very high capacity, although for the price, it tends to be lower capacity than a traditional hard drive. In other words, traditional hard drives are usually a little bit cheaper per gigabyte than a solid state drive is, but you can still get high capacity if you want. And the connection typically, again, is USB, usually USB 3.0 these days, but 2.0 would still be sufficient.

Now network attached storage is certainly still external, but this is not something that you would find in a personal type of scenario. This is usually what you see in a network environment where there are very large demands on the storage. So what you have is an array. You've got multiple hard drives, housed in a single enclosure, and essentially, that's all it is. It's just a big rack of hard drives, so as such, of course, it's not connected locally to a computer using a single cable, it's accessed over the network. It's controlled over the network, and it's still treated like local storage from the perspective of any server that is connected to it. But it does so over an Ethernet port.

Now this is ideal for large scale data backups. And usually it's a very automated process, so once you set it up, it just continues to go automatically. And typically, there's very high capacity here because of the number of drives that you tend to see in network attached storage. And in most cases, you will also see this combined with RAID, Redundant Array of Independent Disks. So that if you get a physical failure of a disk, you can replace that disk without losing any of the data.

Now this can be costly, depending on the size. And there are some limitations with respect to a local backup, depending on the system that you are using. But most server-based systems do fully support network attached storage and they just see it as any other local storage. So backups are usually fine at that level, but maybe not at a desktop level. But again, you really don't see network attached storage in use with desktop computers. But the cost certainly can be prohibitive depending again on how much you need.

Now thumb and flash drives certainly would be bringing us back to the personal storage level. They, of course, are very small in size, so they're very portable. There are still no mechanical parts, so they're certainly reliable. They're very robust in terms of performance. But they tend to have much lower capacity. So it's fine for backing up a small amount of data, but compared to an entire hard drive, we usually have much smaller capacity on thumb and flash drives. But it's really the portability that is their most attractive feature. It makes it very easy to transport data off site and, of course, travel with you with virtually no concern for any extra weight.

And finally, external optical drives are certainly available as well. And these would probably more commonly be for CDs and DVDs, but I'm sure you could find Blu-ray as well. But compared to hard drives, these are still fairly low capacity. A CD is still only 700 megabytes. And DVDs up to around eight and a half gigs. So again, compared to a hard drive, that's certainly low capacity. But they are relatively cheap and easy to acquire. But, again, compared to hard drives, they also have low read/write speeds. It's much faster to read from or write to a hard drive than it is to, say, burn a DVD.

And ultimately, they aren't as reliable. Now that's a matter of perspective, I guess, if you successfully write data to, let's say, a DVD, and you don't have any errors then that data storage itself is quite reliable, but the physical disc is easy to lose and it's easy to damage. So in that regard, it's not as reliable. And even the physical devices themselves, because they are portable, are maybe a little more susceptible to damage. If you have it, let's say in your laptop case and you drop it, there's a reasonable chance that you could damage the device itself. So overall again, not quite as reliable as perhaps some other options. But if it suits your needs, of course, these devices are readily available.

KVM

In this presentation, we'll take a look at the KVM switch, which simply stands for keyboard, video, and mouse. And this is a physical device that allows a user to control multiple computers, but with a single set of peripherals, specifically, your keyboard, your mouse, and your monitor.

So imagine yourself in a situation where you had to maintain, let's just say, three physical computers. And it certainly didn't have to be three, it depended on the device. But if you were physically setting these systems up, and let's just say you had a fairly small table or a small desk, it would be difficult to fit three monitors, three keyboards, and three mice all on that single table. So to save space, you can connect those individual computers to the back of the KVM, which is what you're seeing here.

Then on the opposite side, you would only have a single connection for a single keyboard, a single mouse, and a single monitor. And then typically, there would be some kind of physical switch to change between computers, [Video description begins] An image of the back of a KVM switch displays. There are three panels, each with a keyboard, mouse, and video port. The keyboard and mouse ports are typically color-coded. [Video description ends] maybe a button or a wheel that you could dial, so that the single keyboard, the single mouse, and the single monitor could quite literally be used to manage each computer.

Now this was something that was a lot more common in a data center environment. You generally wouldn't have that kind of configuration at home. But these days, it's a lot less common given the proliferation of virtual machines and remote desktop connections. In either case, you really just wouldn't need a physical KVM.

But there were different types of KVMs out there. And this is essentially with respect to their functionality, and that's centered around the fact that most keyboards and mice these days have USB interfaces. And when you plug in a USB device, the computer invokes what's known as an enumeration process to detect the device and maybe run a short initialization process before it can be used. And with a hub base class, this essentially means that as you switch from system to system, the enumeration process is re-invoked every time. So it's just like plugging in a mouse and a keyboard fresh each time you switch to that computer. So there could be as much as 10 to 15 seconds of latency before the devices will actually work.

Now the emulated class KVM introduced software emulators so that any kind of programmable feature, such as hot keys on the keyboard, will be maintained as you switch from system to system. And because these emulators were present on each system, it believed, if you will, that the devices were always connected. So the latency issue was certainly reduced, but they are still software emulators, so there was still processing involved, which still resulted in some latency. Plus the emulators themselves were quite basic. They only supported a mouse and a keyboard, and only the most basic features of those devices at the time.

Then semi-DDM uses enhanced emulators and a technology known as dynamic device mapping, which supports any type of USB human interface device. That includes, of course, mice and keyboards, but other devices, such as a fingerprint reader to log in or maybe a webcam for facial recognition. But it doesn't retain those connections permanently across all systems, so there was still some latency when switching.

And finally, DDM uses dedicated fully functional emulators across all systems to retain all device functionality for every system. And since it's fully dedicated, there's virtually no latency when switching between systems. So this, of course, is the best class in terms of functionality. But like anything, with greater functionality it will certainly cost a little bit more.

Magnetic and Chip Readers

And beginning with the magnetic stripe, this reads information from cards with a magnetic stripe. Now I'm sure virtually all of us are familiar with this. If you look at the back of your bank card or a credit card, you will undoubtedly find a magnetic stripe. And data is simply encoded into the magnetic stripe in very much the same way you would write to any other magnetic storage.

Now if there's a local connection for the device, you might find a serial port if it's a little bit older. But more commonly these days for newer devices, it would be USB. But in many cases, you might actually see it built right into the keyboard in what's known as a keyboard wedge. This would typically have an extra section that maybe jots out from the top a little bit or maybe along the side. And you simply slide the card through that slot. That's what's known as the keyboard wedge.

But the information is written with an encoder that is in that wedge, or wherever you slide the card through using an electromagnetic writer. And it just uses electrical charges to produce a magnetic field. And changes in that magnetic field are red, and that is how the information is decoded.

Now the chip reader is becoming much more common these days. And this is used to read smart cards, which really is any kind of card with a built-in chip. It's right there on the front of the card in most cases. It's maybe about one centimeter square, usually it's gold in color.

And with respect to reading the information from the card, there are usually two types. A contactless, which uses what's called near-field communication, and we'll actually discuss that in the next presentation, or you physically insert it right into the reader and it's read that way.

And the most common implementation of the chip reader these days is still for a payment card, so a bank card or a credit card. Again, it just allows you to make payments very quickly and easily, particularly if it is contactless. This is just the tap feature for payment systems and you don't have to enter a pin when you use that type of connection. But if it's an insertion, then you'll typically still have to go through the enter a pin option. But again, these are very common with any kind of payment card these days, and are largely replacing the magnetic stripe.

 NFC

Now in this presentation, we'll take a look at NFC, or Near Field Communication, which does enable communication between devices using radio-frequency identification technology, or what's also known as RFID.

Now despite the fact that it is a radio frequency, the communication distance is limited to literally centimeters with NFC. And that is designed to make it a little more secure. You have to have the two devices very close to each other, but it's still not entirely secure. It is still a transmission, so it's possible that someone else can pick up on that, that's known as eavesdropping. And NFC in and of itself does not implement any kind of security, now the application that you're using it for can. But again, just the pure transmission itself is typically not secured. So if the information is picked up through eavesdropping, it could then be modified.

But with respect to applications, such as payment cards, there are protective containers that you can obtain so that you can secure the chips on your cards. And that is a fairly common type of attack these days. An attacker will literally have an RFID scanner and they will try to get as close to you as possible. If, for example, they noticed that you have a wallet in your back pocket, they'll try to get that reader right up against your wallet and try to obtain the information that way. But those containers can be used to secure the cards. They are, I won't say impervious, but certainly a little more resistant, if you will, to scanning.

Now in terms of the common applications, perhaps the most common is the contactless payment system. For any of you who have a chip on your card, and you can use the tap payment option, that's NFC. So again, the idea there is that you have to tap the card pretty much right onto the reader. It will pick it up again if it's just very close to it, maybe a few centimeters away, but usually we just hold it right up against it and it reads the information that way.

But that's not the only application. It's commonly used for sharing data, pictures, and contacts between mobile devices. Now this is sometimes referred to as bootstrapping, but it is effectively just making sure that these two mobile devices are very close to each other and they can then share that information. Android devices call this beaming.

You can also see this used in identity and access tokens. Essentially still smart cards, but not the type of card you would use for a payment system. But rather just something that maybe gives you access to a secure location by unlocking the door. So again you just hold the card up against a reader and it unlocks the door for you.

And you might also find it used in gaming, such as a multi-player game on a mobile device. So, again, if I'm close enough to my friend, and we each have the same type of device, we can play against each other using NFC.

Smart Card Readers

Now, in earlier presentations, we discussed smart cards and near-field communications. But in this presentation, we'll just expand upon this a little bit and talk about the readers and some other applications. Because smart cards are quite versatile, and this really does come down to its data storage ability. You can store a lot more information on a smart card than you can, let's say, on a magnetic stripe.

And with respect to the readers themselves, again, they generally support contact-based or contactless using near-field communication. But again, because of its ability to store information, it's very commonly used to store personal identification information for things like access to secure facilities. And the chip itself is tamper-proof. So if somebody tries to physically access the chip in order to circumvent the information that's stored on it, it essentially self-destructs and becomes unusable. So it can act as a secure data repository for the information on that chip.

So regardless of the application, we, of course, need the appropriate type of reader for it. But when it comes to those applications, we have discussed, of course, banking and retail. So your bankcard and your credit card, of course, will use a chip. But you might also find some kind of an electronic wallet, whereby one device can store the information of multiple payment forms.

It's commonly used for ID verification, again, for access to a secure facility, for example, or any other kind of access control. Maybe it's not so much to get into a physical location, but to be able to access data or information that's stored on a server. You might still need to swipe a card just to be able to log into a system, for example.

Healthcare is another common example where personal information, of course, needs to be stored securely. So you could have some kind of card or system that stores all of that on a smart card.

But regardless, again, of the application, you do need the appropriate type of reader. Now whether it's contact-based or contactless is a function of the application of the card itself. But it is certainly very common to see those NFC types of readers, whereby you just simply tap the card to read the information. But as long as it's something that can read the chip, and do so securely and reliably, then there are a lot of different applications for smart cards.

Identifying Computer Peripherals

Time now, again, for an exercise. And this time, we'll ask you to list the most common types of printers and to describe their basic operation. Then to describe the laser printing process. Then to describe the key characteristics of LCD displays. Then to describe what a lumen value indicates. And finally, to differentiate between magnetic and chip readers.

So, as per usual, what we would like you to do is to take a few moments, pause the recording and jot down some responses. Then we'll come back and review, and we'll see how you made out, so we'll see you shortly.

All right, first we asked to describe the basic printer types and the first is laser. And this uses an electrostatic digital printing process and a focused laser beam to produce the image. Then we have inkjet printers, which use a focused ink spray and the printheads move across the page to produce the image. Then we have the dot matrix printers, which work on an impact principle, whereby pins strike an ink-soaked ribbon onto the paper. And finally, thermal printing, where really it's all in the paper. The image is produced by heating the paper and that causes it to change color. [Video description begins] It uses thermal paper. [Video description ends]

Then we were asked to describe the laser printing process, and this begins with image processing, whereby the image is prepared to be applied to a photoelectric drum. Then charging, uses a corona wire to apply a negative 600 volt charge to the drum. Then exposing, is where the laser focuses onto the drum and essentially drains the charge wherever it's exposed. Developing is the process of the toner being attracted to the discharged areas on the drum. And transferring, uses another corona wire below the paper to apply a positive 600 volt charge, which then attracts the toner from the drum to the paper. And fusing involves heated rollers that melt and press the toner onto the paper. And then cleaning and recharge use a wiper blade to clean away any excess toner and an erase lamp that resets the drum to a neutral charge.

Then we asked to describe the key characteristics of liquid crystal display monitors, or LCD monitors. And typically the characteristics you would want to pay attention to if you are shopping for one would be the screen resolution. Now that typically has a maximum value, but again, it's also dependent on what your computer can produce in terms of the output of the video card. So you don't always just want to go for the highest resolution. In some cases your computer just might not support it, so you could end up paying a little bit more for no reason.

The aspect ratio is the number of pixels on the horizontal versus the vertical. Common ratios include 4 to 3, 16 to 10, or 16 to 9. The display size, of course, but that is measured on the diagonal, let's say from the top-left corner to the bottom-right. And the response time would certainly be something of interest to gamers or anyone who works with high-end graphics in any capacity. Typically, it's measured in milliseconds and it's the time it takes for a pixel to go from dark to light, to dark again or vice versa, light to dark, to light again. So typically, you would want to see something under four milliseconds for a good gaming monitor. But for standard office type of applications, you wouldn't really need anything that fast.

Then we asked to describe what a lumen value indicates. And this is quite simply how bright a projector lamp is. So it really just measures light output, not necessarily watts, that's power consumption. So it is purely concerned with how bright the light is.

Now when shopping for a projector and trying to determine what an appropriate lumen value should be, you do need to consider the ambient light that you're competing with. If you typically deliver presentations in a dark room, then it can be a lower lumen value. But if you are competing with the ambient light of the room itself, then you would certainly want a higher lumen value.

And you might see a range of anywhere between 1500 to 30000, which is quite bright. But that would be maybe for a very large projector in a very large room, such as an auditorium. [Video description begins] The abbreviation for lumens is lm. [Video description ends] For a desktop level projector or something that you would want to travel with, probably around 3000 to 3500 would be more than adequate.

Then finally, we asked to differentiate between magnetic stripe readers and chip readers. And the magnetic stripe reads from information from a card with a magnetic stripe on the back of it. The data is encoded into the magnetic stripe by writing with an encoder, which is essentially just an electromagnetic writer that applies an electric charge to produce a magnetic field. That information is then read by reading the changes in the magnetic field.

But a chip card actually has a chip mounted right on the card itself. So it's used to read what we typically call smart cards, but it literally is built right into the card. Typically, it's on the front. It is maybe about a centimeter square, usually gold in color. And the reader types for that type of card, generally uses NFC or near-field communication for a contactless type, or an insertion, where you leave the card inserted while it's processing the payment or something along those lines. But the contactless is certainly quite convenient, you literally just tap the reader and it reads all of the information. And usually it does not require that you enter any kind of pin or any other information.

So, hopefully, you made out all right with those tasks, and if so, we're ready to move on to our next course.