Glossary
The vocabulary of machine-to-machine technology, in plain words.
- M2M
- Machine-to-machine: the automated exchange of data between devices with no person in the loop. The term comes from telemetry and cellular; it predates “IoT”.
- IoT
- Internet of Things. In practice M2M plus what is built on top: platforms, data, applications. M2M is the plumbing; IoT is the house.
- IIoT
- Industrial IoT — M2M in factories, energy and logistics, where the protocols are older and the uptime requirements harsher.
- LPWAN
- Low-power wide-area network: kilometres of range and years of battery, at the cost of bandwidth. LoRaWAN, Sigfox, NB-IoT and LTE-M all qualify.
- LTE-M (Cat-M1)
- A cut-down LTE for machines: around 1 Mbit/s, mobility and voice support, 1.4 MHz of spectrum.
- NB-IoT
- Narrowband IoT: 180 kHz carrier, tens of kilobits per second, deep indoor coverage. For meters and sensors that send little and rarely.
- RedCap
- Reduced Capability 5G NR, from 3GPP Release 17. Sits between NB-IoT and full 5G — wearables, cameras, industrial sensors.
- NTN
- Non-terrestrial network: satellites and high-altitude platforms carrying standard cellular IoT signals.
- PSM / eDRX
- Power Saving Mode and extended Discontinuous Reception: the two 3GPP features that let a cellular module sleep for hours and still stay registered.
- eUICC
- An embedded SIM whose operator profile can be changed over the air. iSIM goes one step further and moves it inside the main chip.
- Broker
- The server in a publish / subscribe system. Devices never address each other; they publish to topics and the broker routes.
- QoS (MQTT)
- Three delivery levels: 0, at most once; 1, at least once; 2, exactly once.
- DTLS
- TLS adapted to datagrams, so CoAP over UDP can be encrypted.
- OSCORE
- Object security for CoAP: protects the message rather than the connection, so it survives proxies and gateways.
- Attestation
- A signed statement from hardware about what it is and what software it is running.
- FOTA
- Firmware over the air — updating devices in the field without touching them.
- SCADA
- Supervisory control and data acquisition: the control-room systems of utilities and plants, and M2M’s oldest large-scale application.
- Telematics
- M2M in vehicles: position, diagnostics, driver behaviour, emergency call.
- Digital twin
- A live software model of a physical asset, fed by its M2M data.