Friday, 20 May 2011
wireless mouse
wireless keyboard
But you can watch big display well at the distance of 5 feet to 7 feet. You have to need a wireless keyboard and mouse to operate or control the king size computer from far. There are several kinds of wireless keyboard and mouse available in the market which range has been started at some hundred rupees. If you want to take enjoy serial gaming on big screen with computing, you have to need some special kind of wireless keyboard and wireless mouse which is specially developed for gaming. WI key touch of M-KET: with the help of this WI key touch you can control your big screen computer from the distance of 10 meter (30 feet). There are many types of controlling facilities available in WI key touch which adds your enjoy. It is really the wonder of science.
wireless headphone
Philips trotted out its SHD9100 wireless headphones back at IFA in August (where we got to check 'em out first hand), but it looks like the company has just now made the cans available to the general public -- in the U.K., at least. According to Pocket-lint, those in the neighborhood should be able to pick them up now for £170, or about $345. Somewhat curiously, Pocket-lint is also reporting that the cans boast a 50-millimeter speaker driver, and not a 40-mm one as we had heard before, as well as a 30 meter range, as opposed to the 40 meters we last heard about. Otherwise, the phones look to be unchanged, with the same promised six hours of listening time and untold levels comfort and sound quality, which we're guessing you'll want to check out for yourself before dropping all those pounds.
wifi device applications
I might be “out”, but I still feel surprised this evening when I saw a TV report about a so-called “WiFi Stealer” , a wireless device which can detect your WiFi network and try to crack your password, then use your bandwidth to surf the Internet free. And in China, though it is banned to sell it publicly, you can still get such device with about 100~ 200 RMB (about US 15~28$), and the password crack is also quite easy and quick.
I thought my home wireless network is secure and safe. But now I was wrong. And I did some search on the Internet(searching it with Chinese keyword “蹭网卡”). And I saw a lot of such device sellers online. Something like below.
Don’t laugh. Yes, this is true. Its antenna is that long. It is said that it can search the WiFi network within 4 km. Also the seller will provide you a free crack software which can crack the WEP encrypted password within half an hour.
Currently there are three encryptions used by WiFi: WEP, WPA, and WPA2. Though WEP is deprecated (according to wikipedia, today a WEP connection can be cracked with readily available software within minutes), believe it or not, it is still supported and used by WiFi devices. I just looked at my own TP-Link WiFi router, oh my god, I have configured it as my encryption algorithm and my password is only 5 characters long. Though compared with WEP, WPA and WPA2 are enhanced, this doesn’t mean they are safe. Take a look at what wiki reports, http://en.wikipedia.org/wiki/Wi-
bluetooth alert
• Appears as Headset and Hands-Free device on your mobile
• Never miss a call
• never forget your mobile ever again
• universally conpatible with all bluetooth devices
• 100 hour stand-by time
• Resizable neoprene band fits wrists from 7.5″ to 9.5″ around
• 2.4GHz Frequency
• 3 hour charge time
bluetooth headset
Bluetooth Headset
Looking for Bluetooth headset? Auroracell.com carries large selection of Bluetooth device like platonics, jawbone, Motorola, lg, Samsung, blueant, jabra and more. You can find the latest Bluetooth stereo headset and all the new hands free wireless device headset and all the newest Bluetooth technology. All the wireless headset and all the cell phone accessories come with free shipping at the biggest and the cheapest online gsm store. Bluetooth headsets have become must-have for cell phone accessories fanatics particularly in the wake of state and local laws that require the use of a wireless headset while driving. cell phone Bluetooth device usage is not limited to just headsets--you can also use Bluetooth to stream music wirelessly, connect to the Web, transfer files, and more. Bluetooth really is quite simple, inexpensive, and easy to use. In Bluetooth technology, a Bluetooth Headset and a phone communicate with each other over low-frequency radio waves in the 2.4GHz range. No cables or wires are needed, and the only requirement is that both devices be Bluetooth compatible. Bluetooth doesn't cost anything beyond the initial investment in the devices (Bluetooth headsets range from $20-$100). In addition to connecting a cell phone to a headset, Bluetooth is used to connect PCs to keyboards and mice, handhelds to other handhelds, and cell phones to computers. Also on the market is the option for Bluetooth stereo headset for listening to music with a wireless device. Many cars are even equipped with Bluetooth so that you can use the car's audio system for hands-free cell phone functions The process of connecting devices via Bluetooth starts with pairing, a procedure wherein a Bluetooth-enabled phone and another Bluetooth device search for and recognize each other. Once your connection is made and secured via a PIN (personal identification number), the two devices will "talk" to each other and exchange information Its range is limited to 30 feet, which makes it good for connecting a handful of devices but not appropriate for an entire network of computers.
Tuesday, 17 May 2011
wireless networks
What You Need
If you're still using a dial-up modem to access the Internet, it's time to consider broadband. Depending on where you live, you can either opt for a cable or ADSL/DSL solution. A cable solution uses a cable modem such as the Motorola SB4200 SURFboard to connect to an access point, such as those used for cable TV. On the other hand, an ADSL/DSL modem uses the phone line to connect to the Internet. |
| Figure 1. The Motorola SB4200 cable modem |
But the point of this endeavor is going wireless, so we need to find a wireless access point (AP) that comes with a router. The Linksys BEFW11S4 is a good example; it's an 802.11b wireless access point with a four-port switch. 802.11b devices can transmit data at a maximum data rate of 11Mbps, with an effective range of about 150 feet. But don't be misled by these numbers--in practice, you can expect a much lower data rate, and the effective range is dependent on the obstructions placed between your AP and your receiver.
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| Figure 2. The Linksys BEFW11S4 Wireless Access Point with 4-port switch |
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| Figure 3. Rear View of the Linksys BEFW11S4 |
Now let's turn to the wireless portion of things. First, you might have a notebook computer that you want to connect to your home network. For this purpose, you can easily get a wireless PCMCIA card for your notebook, such as the Linksys WPC11.
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| Figure 4. The Linksys PCMCIA 802.11b Wireless Adapter |
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| Figure 5. The Linksys WMP11 802.11b PCI Wireless Adapter |
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| Figure 6. The Linksys WUSB11 USB Wireless Adapter |
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| Figure 7. A Typical Wireless Network Setup |
Configuring Wireless Devices
Once all of the necessary devices are installed, it's not difficult to test the wireless connection. Your wireless adapter comes with utilities to change its settings. In my case, I'm using the software that came with the Linksys PCMCIA card. |
| Figure 8. Examining the Link Quality and Signal Strength of the Wireless Connection |
How WiFi Works
Building a Wireless Network
Photo courtesy Consumer Guide Products
A wireless router uses an antenna to send signals to wireless devices and a wire to send signals to the Internet.
If you already have several computers networked in your home, you can create a wireless network with a wireless access point. If you have several computers that are not networked, or if you want to replace your Ethernetnetwork, you'll need a wireless router. This is a single unit that contains:
A wireless router allows you to use wireless signals or Ethernet cables to connect your computers to one another, to a printer and to the Internet. Most routers provide coverage for about 100 feet (30.5 meters) in all directions, although walls and doors can block the signal. If your home is very large, you can buy inexpensive range extenders or repeaters to increase your router's range.
As with wireless adapters, many routers can use more than one 802.11 standard. 802.11b routers are slightly less expensive, but because the standard is older, they're slower than 802.11a, 802.11g and 802.11n routers. Most people select the 802.11g option for its speed and reliability.
Once you plug in your router, it should start working at its default settings. Most routers let you use a Web interface to change your settings. You can select:
- The name of the network, known as its service set identifier (SSID) -- The default setting is usually the manufacturer's name.
- The channel that the router uses -- Most routers use channel 6 by default. If you live in an apartment and your neighbors are also using channel 6, you may experience interference. Switching to a different channel should eliminate the problem.
- Your router's security options -- Many routers use a standard, publicly available sign-on, so it's a good idea to set your own username and password.
Security is an important part of a home wireless network, as well as public WiFi hotspots. If you set your router to create an open hotspot, anyone who has a wireless card will be able to use your signal. Most people would rather keep strangers out of their network, though. Doing so requires you to take a few security precautions.
It's also important to make sure your security precautions are current. The Wired Equivalency Privacy (WEP) security measure was once the standard for WAN security. The idea behind WEP was to create a wireless security platform that would make any wireless network as secure as a traditional wired network. But hackers discovered vulnerabilities in the WEP approach, and today it's easy to find applications and programs that can compromise a WAN running WEP security.
To keep your network private, you can use one of the following methods:
- WiFi Protected Access (WPA) is a step up from WEP and is now part of the 802.11i wireless network security protocol. It uses temporal key integrity protocol (TKIP) encryption. As with WEP, WPA security involves signing on with a password. Most public hotspots are either open or use WPA or 128-bit WEP technology, though some still use the vulnerable WEP approach.
- Media Access Control (MAC) address filtering is a little different from WEP or WPA. It doesn't use a password to authenticate users -- it uses a computer's physical hardware. Each computer has its own unique MAC address. MAC address filtering allows only machines with specific MAC addresses to access the network. You must specify which addresses are allowed when you set up your router. This method is very secure, but if you buy a new computer or if visitors to your home want to use your network, you'll need to add the new machines' MAC addresses to the list of approved addresses. The system isn't foolproof. A clever hacker can spoof a MAC address -- that is, copy a known MAC address to fool the network that the computer he or she is using belongs on the network.
bluetooth technology
Bluetooth wireless technology is a cable replacement technology that provides wireless communication between portable devices, desktop devices and peripherals. It is used to swap data and synchronize files between devices without having to connect each other with cable. The wireless link has a range of 10m which offers the user mobility. This technology can be used to make wireless data connection to conventional local area networks (LAN) through an access point. There is no need for the user to open an application or press button to initiate a process. Bluetooth wireless technology is always on and runs in the background. Bluetooth devices scan for other Bluetooth devices and when these devices are in range they start to exchange messages so they can become aware of each others capabilities. These devices do not require a line of sight to transmit data with each other.
Within a few years about 80 percent of the mobile phones are expected to carry the Bluetooth chip. The Bluetooth transceiver operates in the globally available unlicensed ISM radio band of 2.4GHz. The ISM bands include frequency range at 902MHz to 928MHz and 2.4GHz to 2.484GHZ which do not require operator license from a regulatory agency. This means that Bluetooth technology can be used virtually anywhere in the world. Another type of wireless technology that is being used nowadays is infrared signals. The choice of using either one of the wireless technology will depend on the application for which it is being used. Bluetooth is an economical, wireless solution that is convenient, reliable, easy to use and operates over a longer distance than infrared. The initial development started in 1994 by Ericsson. Bluetooth now has a special interest group (SIG) which has 1800 companies worldwide. Bluetooth technology enables voice and data transmission in a short-range radio.
There is a wide range of devises which can be connected easily and quickly without the need for cables. Soon people world over will enjoy the convenience, speed and security of instant wireless connection. Bluetooth is expected to be embedded in hundreds of millions mobile phones, PCs, laptops and a whole range of other electronic devices in the next few years. This is mainly because of the elimination of cables and this makes the work environment look and feel comfortable and inviting.
Origin Of Bluetooth
In 1994, Ericsson Mobile Communication initiated a study to investigate the feasibility of a low power, low cost radio interface between mobile phones and their accessories. The aim of the study was to find a way to eliminate cables between mobile phones and PC cards, headsets, desktops and other devices. The study was part of a large project investigating how different communication devices could be connected to the cellular network via a mobile phone. Ericsson's work in this area caught the attention of IBM, Intel, Nokia, and Toshiba. The companies formed the special interest group (SIG) in May 1998, which grew to over 1500 member companies by April 2000. The company jointly developed the Bluethooth 1.0 specifications, which was released in July 1999.
The engineers at Ericsson code-named the new wireless technology Bluetooth to honor a 10th century Viking king in Denmark. Harald Bluetooth reigned from 940 to 985 and is credited not only with uniting that country, but with establishing Christianity there as well. Harald's name was actually Blåtand, which roughly translates into English as 'Bluetooth'. This has nothing to do with the color of his teeth- some claim he neither brushed, nor flossed. Blåtand actually referred to Harald's very dark hair, which was unusual for Viking. Other Viking states included Norway and Sweden, which is the connection with Ericsson (literally, Eric's son) and its selection of Bluetooth as the code- name for this wireless technology
SNAP Wireless LAN I/O
SNAP Wireless LAN I/O™ extends your SNAP Ethernet I/O™ network to areas where it is impossible or uneconomical to run network wiring. Mobile machines and equipment, as well as equipment on the manufacturing floor, in warehouses, and in storage yards, for example, can now be monitored and controlled together with equipment on the wired network or in a separate wireless network.
Used with the same Opto 22 SNAP mounting racks and SNAP I/O™ modules as wired SNAP Ethernet brains, these wireless LAN processors provide a powerful and sophisticated communications and I/O handling system. SNAP wireless LAN brain functions are identical to their analog/digital/serial wired counterparts. The wireless LAN brain also supports the same comprehensive event/reactions and multiple, simultaneous communication options as the SNAP Ethernet brain.
The following diagram shows a network example using both wired SNAP Ethernet I/O and SNAP Wireless LAN I/O. Data from both wired and wireless I/O systems is available to all authorized users on the network for monitoring or control.
SNAP-IT Wireless LAN units are used with Symbol Technologies Spectrum24® access points (APs). An AP acts as a wireless LAN hub to connect wireless devices to each other and to a wired Ethernet network. APs, power supplies and cords, documentation, and a general-purpose antenna can be purchased through Opto 22.
SNAP Wireless LAN I/O can also be used in a completely wireless network, as shown below. A Spectrum24 access point can provide the basis for this wireless network. Wireless devices used with the network, such as wireless laptops, must be equipped with a wireless PC card compatible with the access point. These PC cards and documentation are also available through Opto 22.
For some uses a direct connection between one wireless computer and one SNAP Wireless LAN system may be sufficient. In this case a separate access point is not needed; the wireless PC card in the computer can be set to act as an access point.
wireless network
Wireless network refer to any type of computer network that is not connected by cables of any kind. It is a method by whichtelecommunications networks and enterprise (business), installations avoid the costly process of introducing cables into to a building, or as a connection between various equipment locations.[1] Wireless telecommunications networks are generally implemented and administered using a transmission system called radio waves. This implementation takes place at the physical level, (layer), of the network structure.[2]
wireless lan
A wireless local area network (WLAN) links two or more devices using some wireless distribution method (typically spread-spectrum or OFDM radio), and usually providing a connection through an access point to the wider internet. This gives users the mobility to move around within a local coverage area and still be connected to the network.
Wireless LANs have become popular in the home due to ease of installation, and the increasing to offer wireless access to their customers; often for free. Large wireless network projects are being put up in many major cities: New York City, for instance, has begun a pilot program to provide city workers in all five boroughs of the city with wireless Internet access.[1]
Norman Abramson, a professor at the University of Hawaii, developed the world’s first wireless computer communication network, ALOHAnet, using low-cost ham-like radios. The system included seven computers deployed over four islands to communicate with the central computer on the Oahu Island without using phone lines.[2]
"In 1979, F.R. Gfeller and U. Bapst published a paper in the IEEE Proceedings reporting an experimental wireless local area network using diffused infrared communications. Shortly thereafter, in 1980, P. Ferrert reported on an experimental application of a single codespread spectrum radio for wireless terminal communications in the IEEE National Telecommunications Conference. In 1984, a comparison between infrared and CDMA spread spectrum communications for wireless office information networks was published byKaveh Pahlavan in IEEE Computer Networking Symposium which appeared later in the IEEE Communication Society Magazine. In May 1985, the efforts of Marcus led the FCC to announce experimental ISM bands for commercial application of spread spectrum technology. Later on, M. Kavehrad reported on an experimental wireless PBX system using code division multiple access. These efforts prompted significant industrial activities in the development of a new generation of wireless local area networks and it updated several old discussions in the portable and mobile radio industry.
The first generation of wireless data modems was developed in the early 1980s byamateur radio operators, who commonly referred to this as packet radio. They added a voice band data communication modem, with data rates below 9600-bit/s, to an existing short distance radio system, typically in the two meter amateur band. The second generation of wireless modems was developed immediately after the FCC announcement in the experimental bands for non-military use of the spread spectrum technology. These modems provided data rates on the order of hundreds of kbit/s. The third generation of wireless modem then aimed at compatibility with the existing LANs with data rates on the order of Mbit/s. Several companies developed the third generation products with data rates above 1 Mbit/s and a couple of products had already been announced by the time of the first IEEE Workshop on Wireless LANs."[3]
what is wireless?
Wireless operations permits services, such as long range communications, that are impossible or impractical to implement with the use of wires. The term is commonly used in the telecommunications industry to refer to telecommunications systems (e.g. radio transmitters and receivers, remote controls, computer networks, network terminals, etc.) which use some form of energy (e.g. radio frequency (RF), infrared light, laser light, visible light, acoustic energy, etc.) to transfer information without the use of wires. Information is transferred in this manner over both short and long distances.
In telecommunications, wireless communication may be used to transfer information over short distances (a few meters as in television remote control) or long distances (thousands or millions of kilometers for radio communications). The term is often shortened to "wireless". It encompasses various types of fixed, mobile, and portable two-way radios, cellular telephones, personal digital assistants (PDAs), andwireless networking. Other examples of wireless technology include GPS units, garage door openers and or garage doors, wireless computer mice, keyboards and headsets, satellite television and cordless telephones.
In telecommunications, wireless communication may be used to transfer information over short distances (a few meters as in television remote control) or long distances (thousands or millions of kilometers for radio communications). The term is often shortened to "wireless". It encompasses various types of fixed, mobile, and portable two-way radios, cellular telephones, personal digital assistants (PDAs), andwireless networking. Other examples of wireless technology include GPS units, garage door openers and or garage doors, wireless computer mice, keyboards and headsets, satellite television and cordless telephones.
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