Bluetooth is a proprietary open wireless technology standard
for exchanging data over short distances (using short-wavelength radio
transmissions in the ISM band from 2400–2480 MHz) from fixed and mobile
devices, creating personal area networks (PANs) with high levels of security.
Created by telecoms vendor Ericsson in 1994, it was originally conceived as a
wireless alternative to RS-232 data cables. It can connect several devices,
overcoming problems of synchronization.
Bluetooth is managed by the Bluetooth Special Interest Group, which has
more than 16,000 member companies in the areas of telecommunication, computing,
networking, and consumer electronics, The SIG oversees the development of the
specification, manages the qualification program, and protects the trademarks.
To be marketed as a Bluetooth device, it must be qualified to standards defined
by the SIG. A network of patents is required to implement the technology and
are licensed only for those qualifying devices; thus the protocol, whilst open,
may be regarded as proprietary.
Broadband Internet service truly is the
most used form of Internet access because of its high access speeds; it is
offered in four different forms, DSL (or Digital Subscriber Line), also
fiber-optic, cable, and satellite. The old dial-up connection is the only
non-broadband internet service available, and even though it is cheaper, most
Internet users are moving towards the faster broadband Internet connection.
Infrared
Infrared frequencies are just below visible light. These high
frequencies allow high sped data transmission. This technology is similar to
the use of a remote control for a TV. Infrared transmission can be affected by
objects obstructing sender or receiver. These transmissions fall into two
categories.
- Point to point
- Broadcast
(i) Point
to Point: - Point to
point infrared transmission signal directly between two systems. Many lap top
system use point to pint transmission. These systems require direct alignment
between many devices.
Characteristics
of Point to point:-
- Wide range of cost
- Moderately easy installation.
- 100 k bps to 16 Mb of capacity.
- Variable attenuation.
- High immunity to EMI
(i) Broad
Cast: - These infrared transmission use sprayed signal, one broad cast in
all directions instead of direct beam. This help to reduce the problems of
proper alignment and abstraction. It also allows multiple receiver of signal
Characteristics
of Broad Cast:-
- In expensive.
- Single installation.
- 1M bps capacity.
- Variable attenuation.
