Friday, July 3, 2009

Automation Network Connection

You can automate the connection process for a network or dial-up connection by using the autodial feature. with aautodial enabled, network address are mapped to connection a destination, which allows a destination to be automatically dialed when a remote resources is referenced.

You can also automate the connection process for any Microsoft client by using a simple batch file and the resdial command or by using, Windows NT and Windows 200 application that recognizes remote access.

Atomatic Wireless Internet / Network connection in Windows XP

Windoes XP allows you to established wireless connections to network routers ans accedd points automatically. This feature helps you to make wireless Internet / Wi- Fi network connections more easily with laptop computers and is highly recommended for those who roam between multiple locations.

But not all windows XP computer with Wi-Fi wireless support are capable of automatic wireless configuration. You can verify your wireless network connection properties doing by following method.

1. Start Menu, open windows control panel.

2.Inside control panel, click the " Network Connections" option if it exists, otherwise first click. " Network and Internet conenctions" and then click " Network connections".

3. Finally, right - click " Wireless Network conenction" and choose " Properties".


Friday, June 5, 2009

Wireless Network

In a wireless connection each computer has a wireless network adapter. They connect by sending out ratio waves using a transceiver.

transceiver- A device that can be both transmit and receive signals on local networks( LANs) a transceiver is the device that connect a computer to the network and that converts signals to and from parallel and serial form.

Wireless networking is a way to connect computer or other devices, either in your home or across long distances, using infrared light or radio frequency signals. Devices commonly used for Wireless networking include desktop and laptop computer, hand -held computers, personal digital assistants ( PDAs) , mobile phones, pen based computers, and pagers.

Wireless networking is useful in many situations. For example: If you are travel with a laptop computer you can connect t the internet through wireless access points installed in airports, hotels and other public locations. You can also synchronize data and transfer files between two computers or between a computer and another device.

Wireless local area networks ( WLANs) are often used in corporate or campus buildings, or in airports. WLANs are also used in home or small office networks. there are two types of WLAN.

* A local area network that uses access points to connect computers and devices on the network. This is also called an infrastructure netwok.

* A computer - to- computer local area network ( also called an ad hoc network) with several users in a limited area, such as a conference room. This type of network does not use an access point.

When your computer is in range of a wireless networks Windos XP sends you a message, which appears in the notification area on your screen. You can click the message to see a list of wireless networks and then select a wireless network to connect to. If you are traveling, you can get a list of available wireless networks in the area where you will be staying by entering the city, site or province and postal code for that are.

Sometimes when you connect to a wireless network you are promoted to enter a network key ( also called WEP key, or wired equivalency privacy key). This key is like a password that you need to gain access t the network in some cases, the key might be provides to you by the network administrator. I other cases, you might be asked to create a key.



Wireless Television



Wireless Keyboard

Blue Tooth

Wireless Blue Tooth earphone



Blue tooth wireless technology operates over a short distance. Blue tooth devices use radio transmission, which enables computers. mobile phones, printers, keyboards, mice and other devices to communicate with each other without cables.

The data transfer speeds for blue tooth wireless technology can be up to 700 kilobits ( Kbps) per second. The data transfer speed can vary depending on the device or environmental factors. A Blue tooth device can transmit through walls, pockets and briefcases.



Blue tooth devices transmit on the 2.4 gigahertz (GHz) radio frequently. Devices that transmit on that frequently might not be appropiate or permitted in certain locations, such as hospitals or airplanes. If you are in a potentially sensitive area and you want to use a computer or device using blue tooth wireless technology, check with the staff to ensure that you can do so.

Some mobile phones can be used as a modem for your computer. To find out if your phone has this dial-up newtworking capabilities, read the documentation that came with the phone.

Wireless Blue tooth Mouse



Wireless Blue tooth Speaker

Blue tooth wireless technology




Blue toot cell phone watch

Blue tooth wireless technology is designed to replace cables between devices, such as printers, keyboards and mice.

Blue tooth wireless technology operates over a short distance, Blue tooth devices use radio transmission, which enables computers, mobile phones, printers, keyboards, mice and other devices to communicate with each other without cables.


Blue tooth Key board

There are several users for blue tooth wireless technology, including, but not limited to:

* Creating a wireless connection to the internet with a mobile phone or a modem server.
* Transferring filed between computers or between a computer and another device.
* Printing to a Blur tooth wireless printer.
* Using a blue tooth wireless keyboard and mouse.
* Joining a personal area network (PAN)
* Synchronizing a personal digital assistant (PDA) to a computer or another device using Blue tooth Wireless technology.


Blue tooth IP phone


The data transfer speed for blue tooth wireless technology can be up to 700 kilobits (Kbps) per second. The data transfer speed can very depending on the device or environmental factors. A Blue tooth device can transmit through walls, pockets and briefcases.

Blue tooth transmit in the 2.4 gigahertz ( Ghz) radio frequency that transmit on that frequency might not be appropriate or permitted in certain locations. such as hospitals or airplanes. If you are in a potentially sensitive area and you want to use a computer or device using bluetooth wireless technology, check with the staff to ensure that you can do so.

Speaker

Infrared

Unguided infrared and millimeter waves are widely used for short- range communication. The remote controls used on televisions. VCRs and stereos all use infrared communication. They are relatively directional, cheap and easy to build but have a major drawback. they do not pass through solid objects. In general, as we go from the long wave radio toward visible light, the waves behave more and more like light and less and less like radio.

On the other hand, the fact that infrared waves do not pass through solid walls well is also a plus. It means that an infrared system in one room of a building will not interfere with a similar system in adjacent rooms or buildings; you cannot control your neighbor's television with your remote control. Furthermore, security of infrared system against eavesdropping is better than that radio systems precisely for this reason. Therefore. no government license is needed to operate the ISM bands. Infrared communication has a limited use on the desktop, for example, connecting notebook computers and printers, but it is not a major player in the communication game.

Infrared is located in the components catagory in system information. It contains information about infrared (IR) devices and ports on your system. These devices may not exist on all machines.

Infrared communication

Infrared communication uses infrared ( Light that is beyond red in the color spectrum, while the light is not visible to the human aye. infrared transmitters and receivers can send and receive infrared signals) light to transfer data.

Infrared light is also used almost universally by TV and VCR remote controls. In computers, infrared communication offers an alternative to cables and floppy disks. Infrared communication provides a point-to -point, low-cost way to connect computers with each other or with devices and appliances. Many celluar phones are equipped with infrared ports that allow them to be connected to a computer for dial-up-networking connections.


long range security system device


Infrared Implimentation

Infrared data transfer is implemented according to the infrared data association ( IrDA) standars and protocols. These stands are designed to allow low-cost components and low power requirements, and to enable connections by simply pointing infrared devices at each other. Infrared transceivers are now installed in nearly all new portable computers. For a computer that does not have a bult-in infrared tranceiver, you can install an external infrared transceiver.

IrDA is a half- dulplex, short-range data transfer technology. The IrDA protocols specify the procedures that link initialization, device address discovery, connection startup and data rate negotiation, information exchange, disconnection, link shutdown, and device address conflict resolution.

1) Infrared device support

Infrared functionality is provided through the wireless link file transfer feature, infrared printing (IrPT), infrared image tranfer (IrTran-P) ,and infrared networking ( IrNET and IrComm) capabilities, Additionally, the IrDA Winsock API supports programms created by other software and equipment manufactures. These manufactures sell programs that use the Winsock API ( or proprietary interfaces) to provide infrared conncetions to printers, modems. digital pagers, personal digital assistants, electronic cameras,organizers, celleur phones and hand-held computers.

2) Infrared transmission speeds

Many laptops, notebook computers and hand-held devices now include infrared tranceiver ports that provide infrared asynchronous serial transmission with maximum data transfer speeds of either 115.2 kilobytes per second ( Kbps) or 4 megabits per second ( Mbps) and sometimes 16 Mbps.

Tuesday, May 5, 2009

Links between infrared devices

Infrared data-link transmission occurs between two infrared devices. All transmissions over the link go from the primary ( commanding) device to the secondary ( receiving) device. The primary role is determined dynamically when a link is established and continues until the connection is closed. Any one can assume the primary role, so a user can initiate a data transfer on either computer. Some devices may only be capable of resuming the secondary role.

- How an infrared connection is made

A device creates a link by automatically detecting the other or by a user request. The commanding station sends a connection request at 9,600 bites per seconds (bps) to the other device ( including information such as an address, data rate, and other capabilities). The responding device assumes the secondary role and returns information that contains its address and capabilities. The primary and secondary stations then change the data rate and link parameters to the common set defined by the initial information transfer. Finally, the primary station sends data to the secondary station confirming the connection. The devices are then connected and begin data transfer under control of the primary device.

- Multiple infrared connections

The Winsock API supports multiple simultaneous connections over a single IrDA link. This features allows several different programs to use a single infrared device simultaneously. For example,you might place a portable computer within range of a desktop computer to simultaneously send and receive mail. update your calender and contacts. and print deferred documents. Each activity can be controlled by a separate program on the laptop computer that locates and connects to its corresponding program on the desktop computer.

- Multiple infrared devices

A single infrared device cannot link simultaneously with more than one other infrared device. However, you can install multiple infrared devices on a computer to provide simultaneous links to multiple infrared devices, For example, using separate infrared devices a desktop computer can simultaneously print to an infrared port, communicate with a portable computer =, and diasl a network connection.




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Monday, April 13, 2009

Wireless LAN's ( WIFI)

Almost as soon as notebook computers appeared, many people had a dream of walking into an office and magically having their notebook computer be connected to the internet. Consequently, various groups began working on ways to accomplish this goal. The most practical approach is to equip both the office and the notebook computers with short-range radio transmitters and receivers to allow them to communicate. This work rapidly led to wireless LANs being marketed by a variety of companies.

The trouble was that no two of them were compatible. This proliferation of standards meant that a computer equipped with a brand X radio would not work in a room equipped with brand Y base station. Finally, the industry decided that a wireless LAN standard might be a good idea. so the IEEE committee that standardized the wired LANs was given the task of drawing up a wireless LAN standard. The standard it came up with was named 802.11. A common slang name for it is WIFI. Iy is an important standard and deserves respect. so we will call it by its proper name. 802.11


Wireless Internet

One of the most popular applications for wireless Internet access is the public hot spot. Internet caf├ęs are one example of places where one can sit with a laptop and sip coffee while cruising the Internet, checking email or doing research. Cell phones and personal digital assistants ( PDAs) equipped with Web Browsers can also utilize wireless Internet access points through public hot spots. Some localities provide free wireless Internet access for residents and visitors.

Sunday, April 12, 2009

Wireless Security

It is surprisingly easy to design a system that is logically completely secure by using VPNs and firewalls, but that , in practice,leaks like a sieve. This situation can occur if some of the machines are wireless and use radio communication, which passes right over the firewall in both directions. The range of 802.11 networks is often a few hundred matters, so anyone who wants to spy on a company can simply drive into the employee parking lot in the morninng. leave an 802.11 enabled notebook computer in the car to record everything it hears, and take off for the day. By late afternoon, the hard disk will be full or valuable goodies. Theoretically, this leakage is nor supposed to happen. Theoretically, people are not supposed to rob banks, either.

Much of the security problem can be traced to the manufactures if wireless base stations ( access points) trying to make their products user friendly. Usually if the user takes the device out of the box and plugs it into the electrical power socket, it begins operating immediately -nearly always with no security at all, blurting secrets to everyone within radio range. If it is then plugged in to an Ethernet, all the Ethernet traffic suddenly appears in the parking lot as well. Wireless is a snooper's dream come true; free data without having to do any work. It therefore without saying that security is even more important for wireless systems than for wired ones.

Sunday, April 5, 2009

Code Division Multiple Access (CDMA)


CDMA Phone


CDMA stands for Code Division Multiple Access. It is a technique used for digital communication, and wireless technology in particular, that involve multiplexing. Whereas conventional communication systems use constant frequencies, CDMA uses multiple access, or multiplexing. Multiplexing, in this case accomplished through the specific type known as spread spectrum, uses varied frequencies to transmit audio signals. This, coupled with code division which requires a certain code to send and receive the frequency, further protects CDMA communications from interference.

CDMA Fax Machine