Monday, August 8, 2011

Why Bluetooth is called "Bluetooth"...?

Harald Bluetooth was king of Denmark in the late 900s. He managed to unite Denmark and part of Norway into a single kingdom then introduced Christianity into Denmark. He left a large monument, the Jelling rune stone, in memory of his parents. He was killed in 986 during a battle with his son, Svend Forkbeard. Choosing this name for the standard indicates how important companies from the Nordic region (nations including Denmark, Sweden, Norway and Finland) are to the communications industry, even if it says little about the way the technology works.
The implication is that Bluetooth does the same with communications protocols, uniting them into one universal standard.

Technically speaking,
Bluetooth is essentially a networking standard, originally created by telecom vendor Ericsson in 1994 that works at two levels:

1. It provides agreement at the physical level -- Bluetooth is a radio-frequncy standard.
2. It provides agreement at the protocol level, where products have to agree on when bits are sent, how many will be sent at a time, and how the parties in a conversation can be sure that the message received is the same as the message sent.

It takes small-area networking to the next level by removing the need for user intervention and keeping transmission power extremely low to save battery power.
Bluetooth is managed by the Bluetooth Special Interest Group (SGI), which has more than 14,000 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.

Till this date, Bluetooth has seen several advancements improving its connectivity, data transfer speed, decreasing power consumption etc. Seven versions of Bluetooth are available till now, they are listed below :
  • Bluetooth v1.0 and 1.0B
  • Bluetooth v1.1
  • Bluetooth v1.2
  • Bluetooth v2.0 + EDR(Enhance Data Rate)
  • Bluetooth v2.1 + EDR
  • Bluetooth v3.0 + HS(High Speed)
  • Bluetooth v4.0
Of all these versions, the latest standard covers all older versions.Here is the comparative table of all the versions:
VersionData rateMaximum application throughput
Version 1.21 Mbit/s0.7 Mbit/s
Version 2.0 + EDR3 Mbit/s2.1 Mbit/s
Version 3.0 + HSPerhaps 24 Mbit/s(note: only with AMP, and depends on the AMP. BT itself remains 2.1 Mbit/s max)
Version 4.0Perhaps 24 Mbit/s(note: only with AMP, and depends on the AMP. BT itself remains 2.1 Mbit/s max

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