 Original logo | |||
| Type | Bus | ||
|---|---|---|---|
| Production history | |||
| Designed | 1994 | ||
| Manufacturer | Intel, Compaq, Microsoft, NEC, Digital Equipment Corporation, IBM, Nortel | ||
| Superseded | Serial port, parallel port, game port, Apple Desktop Bus, PS/2 connector | ||
| General specifications | |||
| Length | 5 meters (may be extended with hubs) | ||
| Width | 11.5 mm (A-plug), 8.45 mm (B-plug) (there are also smaller connectors) | ||
| Height | 4.5 mm (A-plug), 7.78 mm (B-plug, pre-v3.0) | ||
| Hot pluggable | Yes | ||
| External | Yes | ||
| Cable | 4 wires plus shield; 9 wires plus shield in USB 3.0 | ||
| Pins | 4 (1 supply, 2 data, 1 ground); 9 in USB 3.0 (additional 5 for SuperSpeed technology including one extra ground); 11 in powered USB 3.0; micro connectors have one additional pin | ||
| Connector | Unique | ||
| Electrical | |||
| Signal | 5 volt DC | ||
| Max. voltage | 5 V(±5%) | ||
| Max. current | 500–900 mA @ 5 V (depending on version) | ||
| Data | |||
| Data signal | Packet data, defined by specifications | ||
| Width | 1 bit | ||
| Bitrate | 1.5/12/480/5,000 Mbit/s (depending on version) | ||
| Max. devices | 127 | ||
| Protocol | Serial | ||
| Pin out | |||
 | |||
| The standard USB A plug (left) and B plug (right) | |||
| Pin 1 | VCC (+5 V) | ||
| Pin 2 | Data- | ||
| Pin 3 | Data+ | ||
| Pin 4 | Ground | ||
Friday, March 30, 2012
Universal Serial Bus
Universal Serial Bus
Universal Serial Bus (USB) is an industry standard developed in the mid-1990s that defines the cables, connectors and communications protocols used in a bus for connection, communication and power supply between computers and electronic devices.[1]
USB was designed to standardize the connection of computer peripherals, such as keyboards, pointing devices, digital cameras, printers, portable media players, disk drives and network adapters to personal computers, both to communicate and to supply electric power. It has become commonplace on other devices, such as smartphones, PDAs and video game consoles.[2] USB has effectively replaced a variety of earlier interfaces, such as serial and parallel ports, as well as separate power chargers for portable devices.
As of 2008[update], approximately 6 billion USB ports and interfaces are currently in the global marketplace, and about 2 billion were being sold each year.[3]
USB was designed to standardize the connection of computer peripherals, such as keyboards, pointing devices, digital cameras, printers, portable media players, disk drives and network adapters to personal computers, both to communicate and to supply electric power. It has become commonplace on other devices, such as smartphones, PDAs and video game consoles.[2] USB has effectively replaced a variety of earlier interfaces, such as serial and parallel ports, as well as separate power chargers for portable devices.
As of 2008[update], approximately 6 billion USB ports and interfaces are currently in the global marketplace, and about 2 billion were being sold each year.[3]
Thursday, March 29, 2012
X-mini MAX II
The X-mini MAX II portable speakers were developed in Singapore. They are the third in the line of XMI's capsule speaker technology. Capsule speakers are quickly becoming a popular alternative to standard portable speakers. These types of speakers have a mushroom-shaped design and are ultraportable. Despite the small size, these audio accessories still deliver powerful sound. The innovative design also includes the option to "pop-up," in order to allow more airflow through the speakers.
Since these X-mini MAX II speakers only require a 3.5mm audio jack, they can be plugged into your desktop computer at work, your laptop in the park or even your MP3 player in the car. Each speaker has a built-in rechargeable battery, so they do not need an external power source. The simple, compact design combined with impressive sound and long battery life makes these speakers TopTenREVIEWS Gold Award winner and the best option found for portable speakers.
The X-mini MAX II capsule speakers have a frequency response of 200Hz~18kHz, which means that they play a wide range of sound. Human hearing generally ranges from 20Hz~20kHz. They do not play as wide a range as home theater speakers or car speakers, but a smaller frequency range is to be expected because of the compact size. These speakers won't play the lowest lows or the highest highs, but they do play frequencies that are comparable to other portable speakers.
Each unit has a 1.57-inch driver, or loudspeaker. Each of these laptop speakers has an output power of 2.5 watts and an impedance of 4 Ohms. These speakers also have a signal-to-noise ratio of 80dB, which means that you can increase the volume fairly high without hearing any additional hissing or buzzing behind the music. It also means that you don't have to turn the dial up too much on these travel speakers in order to get a decent volume level. They are also able to handle high levels of volume with little distortion, which is quite impressive for speakers this small.
You can play one speaker at a time, or hook the two speakers together for a stereo experience. The "Buddy Jack" feature lets you connect one X-mini speaker to another. The cord between the speakers, however, is only three feet. This creates an issue if you're trying to spread them apart for better stereo sound separation. However, each unit has a Buddy Jack system that enables you to hook up another speaker to it. This means that, in theory, you can create a large chain of multiple speakers to play at the same time. Although too many speakers connected together could drive your power source to the limits. The Buddy Jack function can be handy if you're trying to fill a large space with sound. It won't have the sound quality of a professional sound system, but it is a fairly good substitute.
To charge the X-mini MAX II speakers, just plug them into any USB port on your computer or laptop. The built-in rechargeable battery only takes 2.5 hours to charge. After it is fully charged, each capsule speaker has a playback time of up to 12 hours. That kind of battery life is perfect for road trips or camping trips where a power outlet is not readily accessible. There is also a power switch on each individual unit. A blue LED light shows when each unit is powered on, and a red light shows when the speaker is being charged. You can also play the speakers while they are plugged into the computer, giving you an endless supply of power and music.
The X-mini MAX II is an improvement on the X-mini MAX and the X-mini I because of open, angled drivers. It also features a richer bass output than earlier models. Any second generation X-mini speaker is compatible with the Buddy Jack system of these speakers. That means that you can mix and match the models for an even larger audio chain. These speakers are available in black, red and white color options, so you can find one that fits your style.
After switching on each one of the units, these travel speakers are ready to play. There is no volume control on the speakers. They need to be controlled by the computer or MP3 player to which they're attached. To enable the Bass Xpansion System, just twist and lift each speaker and the top will pop up. The speakers can be played without being "popped up," but they achieve a fuller sound when the accordion-style interior is exposed.
Since these X-mini MAX II speakers only require a 3.5mm audio jack, they can be plugged into your desktop computer at work, your laptop in the park or even your MP3 player in the car. Each speaker has a built-in rechargeable battery, so they do not need an external power source. The simple, compact design combined with impressive sound and long battery life makes these speakers TopTenREVIEWS Gold Award winner and the best option found for portable speakers.
Features 
These ultraportable laptop speakers are designed for superior sound. The little capsule speakers expand vertically to enable the Bass Xpansion System. This patented system creates an extendable vacuum, which is capable of producing bass over ten times what the physical size of these speakers would normally allow. The accordion-like design allows for more air to travel through the speakers, creating a resonance similar to a traditional subwoofer. They won't rattle the windows or shake your desk, but these little speakers can keep a beat. The X-mini MAX II capsule speakers have a frequency response of 200Hz~18kHz, which means that they play a wide range of sound. Human hearing generally ranges from 20Hz~20kHz. They do not play as wide a range as home theater speakers or car speakers, but a smaller frequency range is to be expected because of the compact size. These speakers won't play the lowest lows or the highest highs, but they do play frequencies that are comparable to other portable speakers.
Each unit has a 1.57-inch driver, or loudspeaker. Each of these laptop speakers has an output power of 2.5 watts and an impedance of 4 Ohms. These speakers also have a signal-to-noise ratio of 80dB, which means that you can increase the volume fairly high without hearing any additional hissing or buzzing behind the music. It also means that you don't have to turn the dial up too much on these travel speakers in order to get a decent volume level. They are also able to handle high levels of volume with little distortion, which is quite impressive for speakers this small.
You can play one speaker at a time, or hook the two speakers together for a stereo experience. The "Buddy Jack" feature lets you connect one X-mini speaker to another. The cord between the speakers, however, is only three feet. This creates an issue if you're trying to spread them apart for better stereo sound separation. However, each unit has a Buddy Jack system that enables you to hook up another speaker to it. This means that, in theory, you can create a large chain of multiple speakers to play at the same time. Although too many speakers connected together could drive your power source to the limits. The Buddy Jack function can be handy if you're trying to fill a large space with sound. It won't have the sound quality of a professional sound system, but it is a fairly good substitute.
To charge the X-mini MAX II speakers, just plug them into any USB port on your computer or laptop. The built-in rechargeable battery only takes 2.5 hours to charge. After it is fully charged, each capsule speaker has a playback time of up to 12 hours. That kind of battery life is perfect for road trips or camping trips where a power outlet is not readily accessible. There is also a power switch on each individual unit. A blue LED light shows when each unit is powered on, and a red light shows when the speaker is being charged. You can also play the speakers while they are plugged into the computer, giving you an endless supply of power and music.
The X-mini MAX II is an improvement on the X-mini MAX and the X-mini I because of open, angled drivers. It also features a richer bass output than earlier models. Any second generation X-mini speaker is compatible with the Buddy Jack system of these speakers. That means that you can mix and match the models for an even larger audio chain. These speakers are available in black, red and white color options, so you can find one that fits your style.
Portability 
At first glance, the X-mini MAX II portable speakers look like a large egg when put together. The two units are attached to each other by magnetic force. At the widest point, this oval-shaped portable sound machine is only 2.5 inches wide. When the two units are together, it measures just over four inches long. This may make it too big for your pocket, but it is perfect for a backpack or a laptop case. When apart, each speaker is around 2.5 inches high and 2 inches wide. These laptop speakers have a net weight of 0.4 pounds, so you'll hardly feel them in your bag as you're carrying them from place to place. Ease of Use
To detach them from one another, simply twist and pull. Now you're ready to hook the speakers up. These portable speakers come with a cord that includes a USB connection, two mini USB connections and a stereo audio jack. These wires do have a "messy" feel as you're setting them up. The wires cross over one another and seem to be all over the place when everything is set up. Also, there is no in-unit storage for the cord, so you just have to wrap it around the speakers when you're storing it. However, the X-mini MAX II also comes with a storage pouch, so you can just place the cord in the pouch instead of wrapping it around. After switching on each one of the units, these travel speakers are ready to play. There is no volume control on the speakers. They need to be controlled by the computer or MP3 player to which they're attached. To enable the Bass Xpansion System, just twist and lift each speaker and the top will pop up. The speakers can be played without being "popped up," but they achieve a fuller sound when the accordion-style interior is exposed.
Help/Support 
The X-mini site is not very informative or helpful. The information is sparse and the features are minimal. The only question on the FAQs page is "My Unit is faulty, how do I get it replaced?" If you have a question beyond that, there is a contact sheet where you can fill in your information and address a specific issue. No telephone number is given, and no online chat is available at this time. Instructions are included with the product, but no online manual is available. Summary
It is almost impossible to find a portable speaker that has the same sound quality of larger speakers, but the X-mini MAX II comes close. These tiny speakers deliver a full range of sound and an impressive amount of bass. The innovative magnetic design allows the two speakers to become one easy-to-carry audio accessory. In addition, the long battery life makes them ideal for travel. Finally, if you find that these two portable speakers are not loud enough for your needs, you can always "Buddy Jack" them to additional speakers and get the volume you desire.Wednesday, March 28, 2012
ASUS PadFone and upcoming Transformer Pad Lineup unveiled at Mobile World Congress 2012
At today’s “Incredibly Mobile Endless Possibilities” ASUS press event, Chairman Jonney Shih unveiled the revolutionary PadFone and upcoming Transformer Pad lineup with Qualcomm’s CEO and President Paul Jacobs.
“The time has finally arrived when every screen in your lives could transcend into a portal with real time access into your digital world,” said Mr. Shih as he introduced the ASUS PadFone which transforms into a three-in-one combination of a smartphone, a tablet and a notebook when accessorized with the PadFone Station and PadFone Station Dock.
The ASUS PadFone is an incredible 4.3” smartphone featuring a Super AMOLED qHD display, the latest Qualcomm Snapdragon S4 dual-core processor and an ultra-sharp 8-megapixel digital camera with Fuji image processor all wrapped in an exquisite design that is optimized for Google’s Android 4.0 operating system. When placed inside the optional PadFone Station, it transforms into a 10.1” tablet with 5 times the battery capacity. The PadFone offers unmatched versatility via ASUS’ proprietary Dynamic Display technology which allows seamless transition between the PadFone and PadFone Station display screens. In addition, the PadFone Station offers an optional keyboard dock that essentially turns the PadFone into an ultraportable computing device. The PadFone also comes with the option of a PadFone Stylus Headset which is a Bluetooth stylus pen that transforms into a headset for picking up calls easily.
ASUS is redefining the future of mobile computing devices and is excited to announce the new and innovative ASUS Transformer Pad lineup. Offering three distinct models to fit the unique needs of mobile media consumers, ASUS believes in providing consumers with choices. The ASUS Transformer Pad lineup includes the ASUS Transformer Pad Prime and upcoming ASUS Transformer Pad Infinity series and ASUS Transformer Pad 300 series.
The Transformer Pad Infinity Series is poised to be the go-to tablet for HD mobile entertainment as it features an impressive 1920x1200 Full HD Super IPS+ display and ASUS SonicMaster technology. The Transformer Pad 300 Series makes for an ideal mobile web surfing and gaming platform with its NVIDIA® Tegra® 3 quad-core processor and high quality 10.1” 1280x800 IPS display.
“The time has finally arrived when every screen in your lives could transcend into a portal with real time access into your digital world,” said Mr. Shih as he introduced the ASUS PadFone which transforms into a three-in-one combination of a smartphone, a tablet and a notebook when accessorized with the PadFone Station and PadFone Station Dock.
The ASUS PadFone is an incredible 4.3” smartphone featuring a Super AMOLED qHD display, the latest Qualcomm Snapdragon S4 dual-core processor and an ultra-sharp 8-megapixel digital camera with Fuji image processor all wrapped in an exquisite design that is optimized for Google’s Android 4.0 operating system. When placed inside the optional PadFone Station, it transforms into a 10.1” tablet with 5 times the battery capacity. The PadFone offers unmatched versatility via ASUS’ proprietary Dynamic Display technology which allows seamless transition between the PadFone and PadFone Station display screens. In addition, the PadFone Station offers an optional keyboard dock that essentially turns the PadFone into an ultraportable computing device. The PadFone also comes with the option of a PadFone Stylus Headset which is a Bluetooth stylus pen that transforms into a headset for picking up calls easily.
ASUS is redefining the future of mobile computing devices and is excited to announce the new and innovative ASUS Transformer Pad lineup. Offering three distinct models to fit the unique needs of mobile media consumers, ASUS believes in providing consumers with choices. The ASUS Transformer Pad lineup includes the ASUS Transformer Pad Prime and upcoming ASUS Transformer Pad Infinity series and ASUS Transformer Pad 300 series.
The Transformer Pad Infinity Series is poised to be the go-to tablet for HD mobile entertainment as it features an impressive 1920x1200 Full HD Super IPS+ display and ASUS SonicMaster technology. The Transformer Pad 300 Series makes for an ideal mobile web surfing and gaming platform with its NVIDIA® Tegra® 3 quad-core processor and high quality 10.1” 1280x800 IPS display.
Network topology
Network topology is the layout pattern of interconnections of the various elements (links, nodes, etc.) of a computer or biological network. Network topologies may be physical or logical.Physical topology refers to the physical design of a network including the devices, location and cable installation. Logical topology refers to how data is actually transferred in a network as opposed to its physical design. In general physical topology relates to a core network whereas logical topology relates to basic network.
Topology can be understood as the shape or structure of a network. This shape does not necessarily correspond to the actual physical design of the devices on the computer network. The computers on a home network can be arranged in a circle but it does not necessarily mean that it represents a ring topology.
Any particular network topology is determined only by the graphical mapping of the configuration of physical and/or logical connections between nodes. The study of network topology uses graph theory. Distances between nodes, physical interconnections, transmission rates, and/or signal types may differ in two networks and yet their topologies may be identical.
A local area network (LAN) is one example of a network that exhibits both a physical topology and a logical topology. Any given node in the LAN has one or more links to one or more nodes in the network and the mapping of these links and nodes in a graph results in a geometric shape that may be used to describe the physical topology of the network. Likewise, the mapping of the data flow between the nodes in the network determines the logical topology of the network. The physical and logical topologies may or may not be identical in any particular network.
Topology can be understood as the shape or structure of a network. This shape does not necessarily correspond to the actual physical design of the devices on the computer network. The computers on a home network can be arranged in a circle but it does not necessarily mean that it represents a ring topology.
Any particular network topology is determined only by the graphical mapping of the configuration of physical and/or logical connections between nodes. The study of network topology uses graph theory. Distances between nodes, physical interconnections, transmission rates, and/or signal types may differ in two networks and yet their topologies may be identical.
A local area network (LAN) is one example of a network that exhibits both a physical topology and a logical topology. Any given node in the LAN has one or more links to one or more nodes in the network and the mapping of these links and nodes in a graph results in a geometric shape that may be used to describe the physical topology of the network. Likewise, the mapping of the data flow between the nodes in the network determines the logical topology of the network. The physical and logical topologies may or may not be identical in any particular network.
Tuesday, March 27, 2012
WiFi
WiFi uses radio waves for connection over distances up to around 91 metres, usually in a local area network (LAN) environment. Wifi can be used to connect local area networks, to connect cellphones to the Internet to download music and other multimedia, to allow PC multimedia content to be stream to the TV (Wireless Multimedia Adapter), and to connect video game consoles to their networks (Nintendo WiFi Connection).
Infrared Data Association
Infrared Data Association uses infrared light, which has a frequency below the human eye's sensitivity. It is used, for instance, in cell phones, TV remotes and ps3 controllers. Typical WPAN devices that use IrDA include printers, keyboards, and other serial data interfaces
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