Universal Serial Bus

Universal Serial Bus

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Superseded	Serial port, parallel port, game port, Apple Desktop Bus, PS/2 connector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

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]

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.

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.

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.

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.

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

Bluetooth

Bluetooth uses short-range radio waves over distances up to approximately 10 metres. For example, Bluetooth devices such as a keyboards, pointing devices, audio head sets, printers may connect to Personal digital assistants (PDAs), cell phones, or computers wirelessly.
A Bluetooth PAN is also called a piconet (combination of the prefix "pico," meaning very small or one trillionth, and network), and is composed of up to 8 active devices in a master-slave relationship (a very large number of devices can be connected in "parked" mode). The first Bluetooth device in the piconet is the master, and all other devices are slaves that communicate with the master. A piconet typically has a range of 10 metres (33 ft), although ranges of up to 100 metres (330 ft) can be reached under ideal circumstances.
Recent innovations in Bluetooth antennas have allowed these devices to greatly exceed the range for which they were originally designed. At DEF CON 12, a group of hackers known as "Flexilis" successfully connected two Bluetooth devices more than half a mile (800 m) away. They used an antenna with a scope and Yagi antenna, all attached to a rifle stock. A cable attached the antenna to a Bluetooth card in a computer. They later named the antenna "The BlueSniper.

Wireless Personal Area Network

A wireless personal area network (WPAN) is a personal area network - a network for interconnecting devices centered around an individual person's workspace - in which the connections are wireless. Wireless PAN is based on the standard IEEE 802.15. The three kinds of wireless technologies used for WPAN are Bluetooth, Infrared Data Association, and Wi-Fi.
A WPAN could serve to interconnect all the ordinary computing and communicating devices that many people have on their desk or carry with them today - or it could serve a more specialized purpose such as allowing the surgeon and other team members to communicate during an operation.
A key concept in WPAN technology is known as "plugging in". In the ideal scenario, when any two WPAN-equipped devices come into close proximity (within several meters of each other) or within a few kilometers of a central server, they can communicate as if connected by a cable. Another important feature is the ability of each device to lock out other devices selectively, preventing needless interference or unauthorized access to information.
The technology for WPANs is in its infancy and is undergoing rapid development. Proposed operating frequencies are around 2.4 GHz in digital modes. The objective is to facilitate seamless operation among home or business devices and systems. Every device in a WPAN will be able to plug in to any other device in the same WPAN, provided they are within physical range of one another. In addition, WPANs worldwide will be interconnected. Thus, for example, an archeologist on site in Greece might use a PDA to directly access databases at the University of Minnesota in Minneapolis, and to transmit findings to that database.

Personal Area Network

A personal area network (PAN) is a computer network used for communication among computerized devices, including telephones and personal digital assistants. PANs can be used for communication among the personal devices themselves (intrapersonal communication), or for connecting to a higher level network and the Internet (an uplink). A wireless personal area network (WPAN) is a PAN carried over wireless network technologies such as IrDA, Bluetooth, Wireless USB, Z-Wave, ZigBee, or even Body Area Network. The reach of a WPAN varies from a few centimeters to a few meters. A PAN may also be carried over wired computer buses such as USB and FireWire.

Wide Area Network

A Wide Area Network (WAN) is a telecommunication network that covers a broad area (i.e., any network that links across metropolitan, regional, or national boundaries). Business and government entities utilize WANs to relay data among employees, clients, buyers, and suppliers from various geographical locations. In essence this mode of telecommunication allows a business to effectively carry out its daily function regardless of location

Metropolitan area network

A metropolitan area network (MAN) is a computer network that usually spans a city or a large campus. A MAN usually interconnects a number of local area networks (LANs) using a high-capacity backbone technology, such as fiber-optical links, and provides up-link services to wide area networks (or WAN) and the Internet.

Local area network

A local area network (LAN) is a computer network that interconnects computers in a limited area such as a home, school, computer laboratory, or office building.^[1] The defining characteristics of LANs, in contrast to wide area networks (WANs), include their usually higher data-transfer rates, smaller geographic area, and lack of a need for leased telecommunication lines.
ARCNET, Token Ring and other technology standards have been used in the past, but Ethernet over twisted pair cabling, and Wi-Fi are the two most common technologies currently used to build LANs.

Computer network

A computer network, often simply referred to as a network, is a collection of hardware components and computers interconnected by communication channels that allow sharing of resources and information.^[1] Where at least one process in one device is able to send/receive data to/from at least one process residing in a remote device, then the two devices are said to be in a network.
Networks may be classified according to a wide variety of characteristics such as the medium used to transport the data, communications protocol used, scale, topology, and organizational scope.
Communications protocols define the rules and data formats for exchanging information in a computer network, and provide the basis for network programming. Well-known communications protocols are Ethernet, a hardware and Link Layer standard that is ubiquitous in local area networks, and the Internet Protocol Suite, which defines a set of protocols for internetworking, i.e. for data communication between multiple networks, as well as host-to-host data transfer, and application-specific data transmission formats.
Computer networking is sometimes considered a sub-discipline of electrical engineering, telecommunications, computer science, information technology or computer engineering, since it relies upon the theoretical and practical application of these disciplines.

Full-duplex

A full-duplex (FDX), or sometimes double-duplex system, allows communication in both directions, and, unlike half-duplex, allows this to happen simultaneously. Land-line telephone networks are full-duplex, since they allow both callers to speak and be heard at the same time. A good analogy for a full-duplex system would be a two-lane road with one lane for each direction.
Examples: Telephone, Mobile Phone, etc.
Two-way radios can be, for instance, designed as full-duplex systems, which transmit on one frequency and receive on a different frequency. This is also called frequency-division duplex. Frequency-division duplex systems can be extended to farther distances using pairs of simple repeater stations, because the communications transmitted on any one frequency always travel in the same direction.
Full-duplex Ethernet connections work by making simultaneous use of two physical pairs of twisted cable (which are inside the jacket), wherein one pair is used for receiving packets and one pair is used for sending packets (two pairs per direction for some types of Ethernet), to a directly connected device. This effectively makes the cable itself a collision-free environment and doubles the maximum data capacity that can be supported by the connection.
There are several benefits to using full-duplex over half-duplex. First, time is not wasted, since no frames need to be retransmitted, as there are no collisions. Second, the full data capacity is available in both directions because the send and receive functions are separated. Third, stations (or nodes) do not have to wait until others complete their transmission, since there is only one transmitter for each twisted pair.
Historically, some computer-based systems of the 1960s and 1970s required full-duplex facilities even for half-duplex operation, because their poll-and-response schemes could not tolerate the slight delays in reversing the direction of transmission in a half-duplex line.

Half-duplex

A half-duplex (HDX) system provides communication in both directions, but only one direction at a time (not simultaneously). Typically, once a party begins receiving a signal, it must wait for the transmitter to stop transmitting, before replying (antennas are of trans-receiver type in these devices, so as to transmit and receive the signal as well).
An example of a half-duplex system is a two-party system such as a walkie-talkie, wherein one must use "Over" or another previously designated command to indicate the end of transmission, and ensure that only one party transmits at a time, because both parties transmit and receive on the same frequency.
A good analogy for a half-duplex system would be a one-lane road with traffic controllers at each end. Traffic can flow in both directions, but only one direction at a time, regulated by the traffic controllers.
In automatically run communications systems, such as two-way data-links, the time allocations for communications in a half-duplex system can be firmly controlled by the hardware. Thus, there is no waste of the channel for switching. For example, station A on one end of the data link could be allowed to transmit for exactly one second, and then station B on the other end could be allowed to transmit for exactly one second. And then this cycle repeats over and over again.

Simplex

In geometry, a simplex (plural simplexes or simplices) is a generalization of the notion of a triangle or tetrahedron to arbitrary dimension. Specifically, an n-simplex is an n-dimensional polytope which is the convex hull of its n + 1 vertices. For example, a 2-simplex is a triangle, a 3-simplex is a tetrahedron, and a 4-simplex is a pentachoron. A single point may be considered a 0-simplex, and a line segment may be considered a 1-simplex. A simplex may be defined as the smallest convex set containing the given vertices.
A regular simplex^[1] is a simplex that is also a regular polytope. A regular n-simplex may be constructed from a regular (n − 1)-simplex by connecting a new vertex to all original vertices by the common edge length.
In topology and combinatorics, it is common to “glue together” simplices to form a simplicial complex. The associated combinatorial structure is called an abstract simplicial complex, in which context the word “simplex” simply means any finite set of vertices.

Serial communication

In telecommunication and computer science, serial communication is the process of sending data one bit at a time, sequentially, over a communication channel or computer bus. This is in contrast to parallel communication, where several bits are sent as a whole, on a link with several parallel channels. Serial communication is used for all long-haul communication and most computer networks, where the cost of cable and synchronization difficulties make parallel communication impractical. Serial computer buses are becoming more common even at shorter distances, as improved signal integrity and transmission speeds in newer serial technologies have begun to outweigh the parallel bus's advantage of simplicity (no need for serializer and deserializer, or SerDes) and to outstrip its disadvantages (clock skew, interconnect density). The migration from PCI to PCI Express is an example.

Data transmission

Data transmission, digital transmission, or digital communications is the physical transfer of data (a digital bit stream) over a point-to-point or point-to-multipoint communication channel. Examples of such channels are copper wires, optical fibres, wireless communication channels, and storage media. The data are represented as an electromagnetic signal, such as an electrical voltage, radiowave, microwave, or infrared signal.

Analog Transsmission

Analog (or analogue) transmission is a transmission method of conveying voice, data, image, signal or videocontinuous signal which varies in amplitude, phase, or some other property in proportion to that of a variable. It could be the transfer of an analog source signal, using an analog modulation method such as Frequency modulation (FM) or Amplitude modulation (AM), or no modulation at all. 

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