Uses
Bluetooth is a standard wire-replacement communications protocol primarily designed for low power consumption, with a short range (power-class-dependent, but effective ranges vary in practice; see table below) based on low-cost transceiver microchips in each device. Because the devices use a radio (broadcast) communications system, they do not have to be in visual line of sight of each other, however a quasi optical wireless path must be viable.
| Class | Maximum permitted power | Range (m) |
|
|---|---|---|---|
| (mW) | (dBm) | ||
| Class 1 | 100 | 20 | ~100 |
| Class 2 | 2.5 | 4 | ~10 |
| Class 3 | 1 | 0 | ~1 |
The effective range varies due to propagation conditions, material coverage, production sample variations, antenna configurations and battery conditions. In most cases the effective range of Class 2 devices is extended if they connect to a Class 1 transceiver, compared to a pure Class 2 network. This is accomplished by the higher sensitivity and transmission power of Class 1 devices.
| Version | Data rate | Maximum application throughput |
|---|---|---|
| Version 1.2 | 1 Mbit/s | 0.7 Mbit/s |
| Version 2.0 + EDR | 3 Mbit/s | 2.1 Mbit/s |
| Version 3.0 + HS | See Version 3.0+HS. | |
| Version 4.0 | See Version 4.0LE. | |
While the Bluetooth Core Specification does mandate minima for range, the range of the technology is application specific and is not limited. Manufacturers may tune their implementations to the range needed for individual use cases.
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