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Different types of computer keyboards Keyboards are an indispensable accessory for a computer. One of the most basic input devices, computer keyboards are used in navigation, execution of processes, programming and several other purposes. Several software based application directly derive their existence from a keyboard. For instance, social networking websites, programming languages, navigation over the computer menus etc. utilize a computer keyboard. Even this very article wouldn’t have been possible without a keyboard. Different Types of Computer Keyboards A normal computer keyboard is composed of around 110 keys. Although on the basis of key arrangements there are four major keyboard layouts being used worldwide, QWERTY, AZERTY, QWERTZ and HCESAR, but they can be classified in many more different categories depending on types of computer connector, size, number of keys etc. Among the various types listed below, keyboards can be based on multiple types. For instance, an ergonomic keyboard can have a PS2 interface and be an internet keyboard too. ERGONOMIC KEYBOARD The artifact of this keyboard is slightly broader and different in shape, when compared with the normal keyboard. In this key board certain space will be existing between the two sets of keys and the countered shape of this key board allow the users to place their hands in the natural position to type. These key boards are mostly used by the people who often work with the key board as their usage is easier and is less stressful for the wrist. The following figure: Ergonomic keyboard shows how the set of keys are separated with gaps in between. ADB (Apple Desktop Bus) ADB refers to a special type of port which is enabled in some computers such as Apple computers. The ADB key boards can be connected only to the ADB jack enabled computers, but with the use of the adapter, the ADB key boards can also be inserted over a USB port. XT An obsolete type, these keyboards only support the older computers such as IBM 8086/8088, XT-286. Not supported by present computers, keyboards are much larger than the modern keyboards and the “Enter” key is backward-“L” shaped. PERSONAL SYSTEMS (PS/2) In the late 1990, most of the computers are integrated with standard PS/2 connector, rather than USB ports, there by the keyboards used for these computers are usually round pin that fits into the PS/2 keyboard jack. For this reason these keyboards are named as PS/2 keyboards. MINI PS/2 The MINI PS/2 keyboards are very small in size and are compatible with the PS/2 computers. This keyboard resembles the laptop keyboard and it is square in shape. This keyboard is composed of fewer key and do not have detach numeric keypad. MULTIMEDIA The multimedia keyboard is specially designed for the people who are much into multimedia designing. This keyboard is just like the standard key board, but composed of additional keys for the multimedia purposes such as multimedia application launch, volume control and mute button. INTERNET The Internet keyboards are designed for wider range of multimedia applications, these keyboards are specially designed for the intense Internet user. The special keys included in this keyboard are the home key, back and forward key, e-mail launch key, and browser launch key etc. these keys carry out the same functionality as of the buttons on the webpage. In order use these extra keys the computer must be embedded with right operating system. WIRELESS A wireless keyboard, the name itself doles the meaning that this keyboard can be operated without addressing a wired connection to the processor. The wireless keyboards are also referred as Cordless keyboards; these keyboards require batteries to provide the electricity which usually delivered through a PS/2 or USB cable. “AA” or “AAA” batteries are most widely used standard batteries for wireless keyboards. Apple Macs are known to revolutionize the wireless keyboard by making them thinner than the wired ones. These keyboards usually work at 2.4 GHz frequency and come with a dongle that connects and makes them communicate with the computer. GAMING As the name suggest, gaming keyboards are those who are into gaming and need easy access to the keys that are usually utilized in gaming. These keyboards are composed of particular gaming-oriented features such as key lighting, programmable keys, and/or extra controls of volume and brightness. These keyboards are available in wired and wireless, in case if wired, it usually supports the USB port. MEMBRANE Membrane keyboards are one of the keyboard types, which are used very rarely. The keys integrated in this keyboard are non-moving pressure-sensitive keys. The keys in this keyboard are so close, so that there is no scope for spilling liquids into the keyboard. Such keyboard types are also used in mobile phones and old landline phones. Keyboards are slowly being incorporated into touch screens that are being widely incorporated in various phones and tablet computers. Named as touch screen keyboards, these are virtual keyboard units have a QWERTY and numeric appearance so that message typing and number calling are quite easy. Also, gaming consoles that provide social networking such as the PlayStation 3 have an on-screen keyboard which can be accessed by user joystick.

Types of mouse and how they work- explained We are are surrounded with technology. We have computers, we have a really interesting device with which we control almost everything. Any guesses? Exactly, the mouse. And there are different types of mouse. But have you used all of them, wireless, gstick, optical, trackball, mechanical? Let’s talk about all of them and how they work. WIRELESS MOUSE:The Mouse without wire or cord is called wireless mouse or cordless mouse. Most wireless mice use radiofrequency (RF) technology to communicate information to your computer. Since RF devices require two main components: a transmitter and a receiver,thats why wireless mouse also requires it.Working :• The transmitter is housed in the mouse. It sends an electromagnetic (radio) signal that encodes the information about the mouse’s movements and the buttons you click.• The receiver, which is connected to your computer, accepts the signal, decodes it and passes it on to the mouse driver software and your computer’s operating system.• The receiver can be a separate device that plugs into your computer, a special card that you place in an expansion slot, or a built-in component. GSTICK MOUSE:Gordon Stewart designed the Stick to add a more authentic and natural feel to artistic manipulations on both Macs and PCs. These mice are Wireless and pocket-sized. It looks like a pencil. gStick mouse is like a pencil. It can be used for web browsing, office work or whatever you do with your traditional mouse, with more comfort. It also features a scroll wheel that can be manipulated with a finger or thumb a button on either side of the wheel. It’s claimed that a single AAA battery will power the gStick for between three and five months. OPTICAL MOUSE:An optical mouse is an computer pointing device that uses a light-emitting diode an optical sensor, and digital signal processing ( DSP ).This mouse doesn’t have mouse ball and electromechanical transducer. Movement is detected by sensing changes in reflected light, instead of interpreting the motion of a rolling sphere.an optical mouse does not have moving parts thats why there is no need of cleaning .Also there is no mechanical fatigue and failure in this type of mice. The optical mouse takes microscopic snapshots of the working surface at a rate of more than 1,000 images per second. If the mouse is moved, the image changes . The best surfaces reflect but scatter light; an example is a blank sheet of white drawing paper. Some surfaces do not allow the sensor and DSP to function properly because the irregularities are too small to be detected. An example of a poor optical-mousing surface is unfrosted glass. A TRACKBALL MOUSE:A trackball mouse is a pointing device.It consists of a ball held by a socket containing sensors to detect a rotation of the ball. The user rolls the ball with the thumb, fingers, or the palm of the hand to move a pointer. the operator just continues rolling with trackball but a mouse would have to be lifted and re-positioned. Some trackballs, such as Logitech’s optical-pickoff types, have notably low friction, as well as being dense (glass), so they can be spun to make them coast. Large trackballs are common on CAD workstations. MECHANICAL MOUSE OR BALL MOUSE:In 1972, Bill English (builder of Engelbart’s original mouse) invented the ball mouse, while working for Xerox PARC. In this, a single mouse was replaced by the external wheels, which could roll in any direction. Mechanical mouse is a device integrated with an internal metal or rubber ball, which can spin in all directions (left, right, up and down). Thus, the display cursor moves as the mouse detects the direction. The ball in the mechanical mouse spins when it comes in contact with surface on which it is placed.

Types of Computer Cases and Motherboard Factors Before you start Objectives: learn about the common types of computer cases, names and sizes of usual motherboard form factors and which motherboard fits which computer case. Prerequisites: no prerequisites. Key terms: types of computer cases, case size, full tower, mid tower, mini tower, slim line, small form factor, motherboard form factors, atx, micro atx, mini atx, mini itx, btx, nlx, riser card Computer Cases The most common system case type is the tower. Depending on the specific number of internal drive bays and the height of the tower, these cases can be further classified into mini-size, mid-size and full-size tower cases. One of the biggest considerations when choosing between case sizes is the number of slots and the number of devices we would like to add to those cases. Full Tower Full-tower cases are generally big with a height that is about or more than 30 inches (more than 76 cm). The number of internal drive bays inside these cases can be between 6 and 10. Image 113.1 – Tower Computer Case Mid Tower Another case that might be a step down, would be classified as a mid tower case. Mid-tower cases are the most widely used computer cases. Mid Tower cases are about 18 to 24 (45 to 60 cm) inches high and they usually contain 2 to 4 internal drive bays and a similar number of external bays (for CD/DVD readers and similar). Image 113.2 – Mid Tower Computer Case Mini Tower Mini-tower usually have up to 2 or sometimes 3 internal drive bays. Mini-cases normally stand at a height of 12 to 18 inches (30 to 45 cm). Expandability is a problem with these cases. Image 113.3 – Mini Tower Computer Case Slim Line Case Image 113.4 – Slim Line Computer Case Slim line cases are simply tower cases turned on their sideways. They can hold a monitor on top of the case. Small Form Factor (SFF) Case Small form factor or SFF cases are custom cases that are designed to minimize the spatial volume of a desktop computer. SFFs are available in a variety of sizes and shapes, including shoe boxes, cubes, and book-sized PCs. Image 113.5 – Small Form Factor Computer Case Motherboard Form Factor There’s one important consideration we need to be aware of when choosing the case size and that is the size of the motherboard. They need to match. The size of the motherboard is often called the Form Factor and there are several standards. The form factor identifies the size of the circuit board, the location of the slots as well as the location of the faceplate that comes out the back of the computer. The form factor also identifies the location of the holes that are used to mount the motherboard into the system case. For example, the full tower has more than enough room to fit an ATX motherboard. Mid-tower case can also accommodate an ATX motherboard in most cases. ATX Form Factor (Full ATX) Probably the most common form factor for a motherboard is the ATX form factor. The board is approximately 12″ x 9.6″ (30cm x 24cm). Image 113.6 – ATX Form Factor Mini ATX A mini-ATX motherboard is a slightly smaller variation of the full ATX size that measures 11.2″ x 8.2″ (28cm x 21cm). The main difference between ATX and mini-ATX is the number of buses and possibly memory slots on the motherboard. Mounting holes for both are located in the same place, making them interchangeable in most cases. A case that supports an ATX motherboard can also support mini-ATX motherboard. Micro ATX The micro-ATX form factor is an even smaller version of the ATX standard, with a maximum size of 9.6″ x 9.6″ (24cm x 24cm). The faceplate line up to the exact same position as in all other versions of ATX. System case that can hold an ATX motherboard can also hold micro ATX motherboard. The smaller mid or mini tower cases would likely be too small for a full ATX motherboard but should accommodate micro ATX motherboard. The terms mini-ATX and micro-ATX are often used interchangeably. Image 113.7 – Micro ATX Form Factor Flex ATX The size of Flex ATX is 9” x 7.5” (22,9 cm x 19,1 cm). It is derived from Micro ATX and is used in small computer cases. Flex ATX Form Factor Mini ITX Going down in size we have a mini ITX motherboard with a maximum size of 6.7″ x 6.7″ (17cm x 17cm). Notice that there is a single expansion slot and the motherboard itself is considerably smaller than the ATX and even the micro ATX. Also notice that the faceplate still line up and the hole positions still match the ATX hole positions. Theoretically we could take this micro ITX motherboard and place it inside a full tower case. However we usually use a small form factor case for this motherboard. Image 113.8 – Mini ITX Form Factor Em ITX Em ITX dimensions are 17 cm x 12 cm. Em ITX Form Factor Nano ITX Measures of Nano ITX are 4.7″ x 4.7″ (12 cm x 12 cm). It is used with smaller devices like set-top boxes, car PCs, media centers, and other embedded devices. Nano ITX Form Factor Pico ITX The size of the Pico ITX is 3.9” x 2.8” (10 cm X 7,2 cm). Pico ITX Form Factor Mobile ITX Mobile ITX is the smallest form factor with the size of 2.4” x 2.4” (6 cm x 6 cm). Mobile ITX Form Factor The ATX form factor and its variations are the most common motherboard form factors. DTX Form Factor DTX form factor is intended for small form factor PCs, and is backward compatible with ATX form factor cases. Dimensions are 8” x 9.6” (20,3 cm x 24,4 cm). DTX Form Factor Mini DTX Mini DTX is a shorter version of DTX form factor. Dimensions are 8” x 6.7” (20,3 cm x 170 cm). Mini DTX Form Factor SSI CEB SSI form factors were developed by SSI (Server System Infrastructure) forum, and are intended for dual or multi processor motherboards used in servers and or even workstations. SSI form factors were derived from ATX specification, so they have the same rear panel, IO connector area, and mounting holes. But, SSI form factors are larger than ATX, so SSI motherboards will not fit cases designed for standard ATX. The computer case has to be designed for larger than standard ATX form factor.Three SSI form factors are CEB (Compact Electronics Bay), EEB (Enterprise Electronics Bay), and MEB (Midrange Electronics Bay). The smallest of them is SSI CEB, and the size is 12” x 10.5” (30,5 cm x 26,7cm). SSI CEB Form Factor SSI EEB (also called Extended ATX or E-ATX) SSI EEB dimensions are 12” x 13” (30,5 cm x 33 cm). SSI EEB Form Factor SSI MEB The SSI MEB size is 16.2” x 13” (41,1 cm x 33 cm). It is longer in order to provide space for two additional CPU sockets. SSI MEB Form Factor BTX Form Factor There are a few main differences with the BTX form factor. Notice that the faceplate is on the opposite end. Another difference is that the hole positions are different. Also, the processor socket is slightly rotated so that it is at an angle to the system board. This rotation is to aid in the airflow across the processor to assist in cooling the processor. The BTX motherboard will only fit within a system case that is designed for a BTX motherboard. In many cases this means that an ATX system case will not work with a BTX system board, although there are system cases that are able to accommodate both the ATX and the BTX form factors. The BTX form factor has not been widely adopted despite its improvements over ATX and related standards. As a result, the availability and variety of BTX-compatible components is limited. Image 113.9 – BTX Form Factor NLX Form Factor The NLX is an older style form factor that is not used very often anymore. We might see it in some older motherboards but it’s not likely to encounter it with newer motherboards. Image 113.10 – NLX Form Factor NLX is an older form factor used for slimline desktop-style computers. NLX is an improvement over an even earlier LPX form factor. Notice that this motherboard has no expansion slots for the PCI or ISA bus. The NLX form factor is used in slim line cases that are very short. Image 113.11 – NLX With Riser Card In order to accommodate expansion cards we use a tab on the edge of the motherboard. We insert a Riser Card on the end of the motherboard. Riser Card is then used for expansion cards, so that now expansion cards lay flat rather than being perpendicular to the motherboard. The riser card does not have built-in ports for audio, joystick, USB, network or modem. Remember When choosing a system case, other than considering the size of the computer that we want, the most important thing is to match the motherboard form factor with the form factor supported by the computer case. The most common system case type is the tower. Tower cases are: Full tower, Mid tower and Mini tower. Slim line cases are simply tower cases turned on their sideways. Small form factor or SFF cases are custom cases that are designed to minimize the spatial volume of a desktop computer. The size of the motherboard is often called the Form Factor. The most common form factor for a motherboard is the ATX form factor. When considering the size of ATX we differentiate Full ATX, Mini ATX, Micro ATX, Flex ATX, Mini ITX, Em ITX, Nano ITX, Pico ITX, Mobile ITX. SSI CEB, SSI EEB, SSI MEB form factors are larger than ATX. When comparing with ATX, BTX form factor has the faceplate on the opposite side, hole positions are different and the processor socket is slightly rotated. The BTX motherboard will only fit within a computer case that is designed for a BTX motherboard. The NLX is an older style form factor that is not used very often anymore.

Guide to Computer Cables and Connectors Computer cables can be confusing so here’s a guide that will help you identify cables, connectors and converters that came with your computers and other electronic gadgets.couch modeprint story Neatly Organize USB Cables and Charging Cords on your Desk How to Connect an External Microphone to your iOS Device How to Connect Two Computers Without a Router Keep your Mobile Phone Safe at a Public Charging Station How to Make Your Wired Printer Wireless Computer cables are confusing to most users. Here’s a visual guide to help you quickly identify all the common cable and connectors that came bundled with your computers, mobile phones and other electronic gadgets. You may also refer to this guide for ideas on how to hook different devices using commonly available connectors and converters. Also see: Organize Computer Cables with Binder Clips 1. USB Cables and Connectors You can use USB cables to connect most new devices to your computer including flash memory sticks, portable media players, internet modems and digital cameras. Computer accessories like mice, keyboards, webcams, portable hard-drives, microphones, printers, scanners and speakers can also be connected to the computer through USB ports. Additionally, USB cables are also used for charging a variety of gadgets including mobile phones or for transferring data from one computer to another. How to recognize USB Cables – The standard USB connector, USB-A, is a rectangular connector. The USB-A end is present on every USB cable as it is the end that connects to your computer. The other end of the USB cable may have different connectors including USB-B (a square connector commonly used with printers, external hard drives, and larger devices) or smaller connectors such as the Mini-USB and Micro-USB that are commonly used with portable devices such as media players and phones. Additionally, many other connectors have USB-A connectors at the end that connects to the computer, and a device-specific connector at the other end (e.g. the iPod or a Zune). Then you have USB Male to Female connectors for extending the length of a USB cable. Many other non-USB cables can also connect to your computer via a USB converter; these cables have the standard USB-A connector on one end while the other end could have connections for other ports such as Ethernet or audio. 2. Audio Cables and Connectors 2.1 – 3.5mm headphone jack The most common audio cable is the standard headphone jack, otherwise known as a TSR connector. It is available in several sizes, but the most common ones used with computers are the 3.5 mm or 1/8″ mini audio jack. Most speakers and microphones can connect to the computer with these audio cables. The microphone port on your computer is usually pink while the speaker port, where you insert the stereo audio cable, is colored green. Some computers have additional TSR audio ports colored black, grey, and gold; these are for rear, front, and center/subwoofer output, respectively. A larger variety of the TSR connector, 1/4″ TRS, is commonly used in professional audio recording equipment and it can be connected to a computer using an 1/4″ to 1/8″ converter (pictured right). 2.2 – Digital Optical Audio For high-end audio, like when you want to connect the output of a DVD player or a set-top box to a Dolby home theater, you need the TOSLINK (or S/PDIF) connector. These are fiber optic cables and can therefore transmit pure digital audio through light. Some laptops and audio equipment have a mini-TOSLINK jack but you can use a converter to connect it to a standard TOSLINK (Toshiba Link) port. 3. Video Cables 3.1 – VGA One of the most common video connectors for computer monitors and high-definition TVs is the VGA cable. A standard VGA connector has 15-pins and other than connecting a computer to a monitor, you may also use a VGA cable to connect your laptop to a TV screen or a projector. Converter cables are lso available to let VGA monitors connect to newer computers that only output HDMI or DVI signals. A smaller variant of VGA, Mini-VGA, is available on some laptops but with the help of a converter, you can connect any standard VGA monitor to a Mini-VGA port of your laptop. Related: How to Connect your Laptop to a TV Set 3.2 – DVI Monitor Port If you have purchased a computer in the recent past, chances are that it uses DVI instead of VGA. The new breed of “thin” laptops use the smaller variants of DVI like the Mini-DVI and Micro-DVI (first seen in MacBook Air). A DVI cable has 29 pins, though some connectors may have less pins depending on their configuration. DVI’s video signal is compatible with HDMI, so a simple converter can allow a DVI monitor to receive input from an HDMI cable. Additionally, DVI to VGA converters are also available for connect your new graphics card to old monitor that supports only VGA mode. 3.3 – S-Video S-Video cables, otherwise known as Separate Video or Super Video cables, carry analog video signals and are commonly used for connecting DVD players, camcorders, older video consoles to the television. Standard S-Video connectors are round in shape and may have anywhere between 4-9 pins. 4. Audio and Video Cables 4.1 – RCA Connector Cables RCA connector cables are a bundle of 2-3 cables including Composite Video (colored yellow) and Stereo Audio cables (red for right channel and white or black for the left audio channel). Sometimes additional cables may be included, offering additional audio channels and/or component video instead of composite. Component video offers better picture than composite because the video signal is split in different signals while in the case of composite, everything is transferred through a single yellow plug. Uses of RCA Connectors – The RCA cables are usually used for connecting your DVD player, stereo speakers, digital camera and other audio/video equipment to your TV. You can plug-in an RCA cable to the computer via a video capture card and this will let you transfer video from an old analog camcorder into your computer’s hard drive. 4.2 – HDMI Cables HDMI is the new standard that provide both audio and video transmission through a single cable. HDMI support a maximum resolution of 4096×2160p (HD is only 1920×1200) with up to 8 channels of digital audio and are used for connecting Blu-Ray players to an HDTV. Standard HDMI cables can be up to 5 meters long, but higher quality ones can be up to 15 meters long, and the length can be further increased with amplifiers. HDMI is backwards compatible with DVI so you can use a converter to watch video on a DVI device through the HDMI cable though you will have to use another cable for the audio. 4.3 – DisplayPort A combined digital video and audio cable that is more commonly used in computers is DisplayPort and the smaller derivative Mini DisplayPort. Both support resolutions up to 2560 × 1600 × 60 Hz, and additionally support up to 8 channels of digital audio. Mini DisplayPort connector is currently used in MacBooks but we could them in other computers as well in the near future. Standard DisplayPort cables can be up to 3 meters long, but at a lower resolution cables can be up to 15 meters long. DisplayPort connectors are available to connect VGA, DVI video, or HDMI video and audio with a DisplayPort cable or connection. Additionally, converters are available to convert Mini DisplayPort into standard DisplayPort. 5. Data Cables 5.1 – Firewire IEEE 1394 Firewire, otherwise known as IEEE 1394, i.LINK, or Lynx, is a faster alternate to USB and is commonly used for connecting digital camcorders and external hard drives to a computer. It is also possible to ad-hoc network computers without a router over FireWire. Firewire typically has 6 pins in its connector, though a 4 pin variety is common as well. 5.2 – eSATA Cables While SATA cables are used internally for connecting the hard drive to the computer’s motherboard, eSATA cables are designed for portable hard drives, and can transfer data faster than USB or FireWire. However, the eSATA cable cannot transmit power, so unlike USB, you cannot power an external hard drive with eSATA. The eSATA cable is somewhat different from the internal SATA cable; it has more shielding, and sports a larger connector. 6. Networking Related Cables 6.1 – Phone RJ11 Cable The telephone cable, otherwise known as RJ11, is still used around the world for connecting to the Internet through DSL/ADSL modems. A standard phone cable has 4 wires and the connector has four pins. The connector has a clip at the top to help maintain a tight connection. 6.2 – Ethernet Cable Ethernet is the standard for wired networking around the world. The Ethernet cable, otherwise known as RJ45, is based on Cat5 twisted pair cable and is made from 8 individual wires. The Ethernet connector, likewise, has 8 pins and looks similar to a phone plug, but is actually thicker and wider. It too has a clip to help maintain a tight connection like a phone connector.