Networking · Topic 4 of 10
Bluetooth, NFC, RFID and Cellular
Compare short range and low power wireless technologies such as Bluetooth, NFC, RFID, Zigbee and Z-Wave with cellular 4G and 5G data networks.
- 4 min
- Bluetooth is a 2.4 GHz personal area link of around 10 metres that needs pairing.
- NFC works only over a few centimetres and is used for payments and access.
- RFID uses tags and readers; passive tags have no battery and active tags do.
What it is
Wi-Fi is not the only wireless technology a technician meets. Short range links connect headsets, payment cards, door badges and smart home sensors, while cellular networks connect phones and some laptops across wide areas.
This page compares the main ones by range, purpose and typical use.
How it works
Each technology trades range for power use, speed and cost.
Bluetooth
Bluetooth is a short range radio link on the 2.4 GHz band for personal devices. Typical range is about 10 metres for common devices, and higher power classes reach further.
It supports headsets, speakers, keyboards, mice, watches and car systems. Devices must be paired first. Bluetooth shares the 2.4 GHz band with some Wi-Fi, so crowding can cause audio drops.
Near field communication
Near field communication (NFC) works over a few centimetres, so the two devices almost touch. It needs very little power and often needs no battery in the tag or card.
Typical uses are contactless payment, transit passes, door entry and a tap to start a Bluetooth pairing.
Radio frequency identification
Radio frequency identification (RFID) uses a tag and a reader. The reader sends a radio signal, and the tag answers with its stored identity.
- Passive tags have no battery and take their power from the reader's signal.
- Active tags have their own battery and can be read from further away.
Uses include stock tracking, access badges, pet microchips and toll tags. NFC is a short range form of the same idea with two way exchange.
Zigbee and Z-Wave
Both are low power wireless standards for smart home and Internet of Things (IoT) devices, such as sensors, bulbs and locks. Both can pass data from device to device, forming a mesh, which extends their reach.
| Technology | Band | Notes |
|---|---|---|
| Zigbee | Mostly 2.4 GHz | Open standard, low power, mesh network |
| Z-Wave | Below 1 GHz | Built for home automation, mesh network, less crowded band than 2.4 GHz |
A hub or controller usually sits between these devices and the home network.
Cellular
Cellular networks cover wide areas with towers that connect phones, tablets and mobile hotspots. The carrier owns the licensed spectrum and charges for service.
| Generation | Name | Notes |
|---|---|---|
| 4G | Long Term Evolution (LTE) | Widely used for mobile data |
| 5G | Fifth generation | Higher speed, lower delay, many devices per area |
The bands used for cellular data differ from Wi-Fi, and coverage depends on the carrier's towers. Cellular is used for phones, hotspots and some branch or backup internet links.
Choosing the right technology
| Need | Choose |
|---|---|
| Wireless headset or mouse | Bluetooth |
| Tap to pay or open a door | NFC |
| Track items or badges | RFID |
| Battery powered smart home sensors | Zigbee or Z-Wave |
| Internet access on the move | Cellular |
If a question mentions touching or tapping devices within a few centimetres, the answer is NFC. If it mentions tags and readers for inventory, the answer is RFID.
What to remember for the exam
- Bluetooth is a 2.4 GHz personal area link of around 10 metres that needs pairing.
- NFC works only over a few centimetres and is used for payments and access.
- RFID uses tags and readers; passive tags have no battery and active tags do.
- Zigbee and Z-Wave are low power mesh technologies for smart home devices.
- Z-Wave uses a band below 1 GHz; Zigbee is mostly on 2.4 GHz.
- 4G LTE and 5G are cellular standards that carriers provide over licensed spectrum.
- A smart home hub often links Zigbee or Z-Wave devices to the network.
- Bluetooth and Wi-Fi share the 2.4 GHz band and can disturb each other.
Common mistakes
Mixing up NFC and Bluetooth. NFC is for a touch, a few centimetres, while Bluetooth covers several metres.
Assuming RFID tags need batteries. Passive tags take their power from the reader.
Confusing Zigbee and Z-Wave bands. Zigbee is mostly 2.4 GHz and can clash with Wi-Fi, while Z-Wave uses a lower band.
Using cellular terms for Wi-Fi. 4G and 5G belong to carriers, while 802.11 standards belong to Wi-Fi.
Forgetting pairing. Bluetooth devices connect only after a pairing step, even when they are close together.
Check yourself
Which technology works within a few centimetres and is used for tap to pay?
Near field communication (NFC).
What is the difference between passive and active RFID tags?
Passive tags have no battery and use the reader's signal, while active tags have their own battery and longer range.
Which two low power standards form mesh networks for smart home devices?
Zigbee and Z-Wave.
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