---
title: "Major characteristics of Bluetooth"
subject: "Instrumentation II"
chapter: 5
key: "semester_5/instrumentation_ii:bt-characteristics"
source: https://www.bctengineer.com/q/semester_5/instrumentation_ii/bt-characteristics
site: BCT Engineering
---

# Major characteristics of Bluetooth

Instrumentation II · Chapter 5: Data Acquisition And Transmission

- Asked in: 2078 Bhadra, 3 marks
- Video: [IEEE 802.15.1 Bluetooth](https://www.youtube.com/watch?v=ixY0Cau4mBM) — Neso Academy
- Answer checked by Claude Sonnet 5.5 on 2026-10-14
- Page: https://www.bctengineer.com/q/semester_5/instrumentation_ii/bt-characteristics
- Whole chapter: https://www.bctengineer.com/md/semester_5/instrumentation_ii/chapter-5

## Question

List the major characteristics of Bluetooth.

## Short answer

Bluetooth uses 2.4 GHz ISM band, frequency hopping over 79 channels at 1600 hops/s, GFSK (and EDR) modulation, 1–3 Mbps rates, piconet with one master and up to seven slaves, TDD slots, low power with ranges up to 100 m, and supports SCO/ACL links.

## Answer

Major characteristics of Bluetooth:

1. **Frequency band:** 2.4 GHz ISM band (2.402-2.480 GHz), licence free.
2. **Spread spectrum:** frequency hopping over 79 channels of 1 MHz, 1600 hops/s.
3. **Modulation:** GFSK (1 Mbps); EDR uses pi/4-DQPSK and 8DPSK (2-3 Mbps).
4. **Data rate:** 1 Mbps (v1.x), 3 Mbps (EDR), up to 24 Mbps (high speed); BLE 1-2 Mbps.
5. **Range:** class 1 about 100 m (100 mW), class 2 about 10 m (2.5 mW), class 3 about 1 m (1 mW).
6. **Topology:** piconet (1 master + 7 active slaves) and scatternet.
7. **Time division duplex** with 625 us slots; SCO links (voice) and ACL links (data).
8. **Low power and low cost,** small chips; BLE for coin-cell devices.
9. **Security:** pairing, authentication and encryption.
10. **Ad hoc, automatic connection** and service discovery; omnidirectional, no line of sight needed.

## Check yourself

The answer's key points as multiple-choice questions, with the correct option and why.

1. In which band does Bluetooth operate?
   A. 900 MHz licensed band
   B. 5 GHz licensed band
   C. 60 GHz band
   D. 2.4 GHz ISM band, licence free
   Answer: D. 2.402-2.480 GHz ISM. (Key point: Frequency band)

2. How is range related to class?
   A. Class 1 about 100 m, class 2 about 10 m, class 3 about 1 m
   B. Class 1 about 1 m, class 3 about 100 m
   C. All about 10 m
   D. Class 2 about 100 m
   Answer: A. Higher power class gives longer range. (Key point: Range classes)

3. Which describes Bluetooth topology and links?
   A. Star of 15 masters, FDD
   B. Piconet of 1 master and 7 active slaves, TDD with 625 us slots, SCO for voice and ACL for data
   C. Bus with 8 masters
   D. Ring, SCO for data
   Answer: B. Bluetooth uses TDD slots with SCO and ACL links. (Key point: Topology and links)

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