wifi

What is Wi-Fi :

What is Wi-Fi Wi-Fi is an abbreviation for Wireless Fidelity and a catch all phrase for the several different standards and recommendations that comprise wireless networking . Wi-Fi enables the user to deploy a computer network without needing to run cable throughout the facility.

Standards:

Standards IEEE 802.11.b –2.4GHz – 11Mbps IEEE 802.11.a – 5GHz – 54 Mbps IEEE 802.11g – 2.4Ghz – Hybrid 11/54Mbps 802.11g is in the final stages of development. The current draft (V5.0) is open for comments until January 8, 2003.

Wireless Network Components:

Wireless Network Components Access Points NICs – Network Interface Cards PCMCIA USB PCI CompactFlash Other Wireless Devices Bridges and Routers Print Servers PCs, Laptops, PDAs

Limitations :

Limitations 300 ft. effective range from access point 1400 ft maximum range Structural interference Interference from other devices such as cordless phones.

Applications :

Applications Any application currently used on a traditional wired network can be used on a wireless network. New applications may be available or can be developed to take advantage of wireless, such as Wireless PDA access to a card catalog.

INFRARED:

INFRARED Wireless infrared communications refers to the use of free-space propagation of light waves in the near infrared band as a transmission medium for communication. The communication can be between one portable communication device and another or between a portable device and a tethered device, called an access point or base station . Although infrared light is usually used, other regions of the optical spectrum can be used.

INFRARED:

Transmitting binary ones and zeros via infrared light is not as complicated as it may appear at first glance. Just as radio stations transmit information using radio waves, infrared devices transmit data using the infrared frequencies of the electromagnetic spectrum. All sending and receiving IR devices contain small, dark windows called IR ports. Inside these ports, transceivers send and receive data using the IR frequency . INFRARED

INFRARED:

After a device's CPU sends the binary ones and zeros to the software controlling the IR transmission process, that information is converted into pulses of IR light. The software then forwards the data to the device's transceiver, which transmits the IR signals to another IR port. The receiving device's IR software converts the infrared transmission back into binary digits. INFRARED

APPLICATION:

APPLICATION

Slide 10:

Bluetooth, named for Denmark's first Christian king and not a dire dental condition, is the name of a technology specification for small form factor, low-cost, short-range radio links between PCs, handhelds, mobile phones, and other computing and electronic devices. Bluetooth technology provides a 10-meter personal bubble that supports simultaneous transmission of both voice and data for multiple devices. Up to 8 data devices can be connected in a piconet , and up to 10 piconets can exist within the 10-meter bubble

Slide 11:

Any Bluetooth device can be a master or a slave, depending on the application scenario. Bluetooth employs frequency hopping spread spectrum (FHSS) to communicate. So in order for multiple Bluetooth devices to communicate, they must all synchronize to the same hopping sequence. The master sets the hopping sequence, and the slaves synchronize to the Master. A piconet is formed by a master and up to seven active slaves. The slaves in a piconet only communicate with the master.