This glossary includes key terms of the IoT (Internet of Things) & M2M (machine-to-machine) communications industry, including wireless and cellular technologies spanning many different markets. It is updated to present current terminology and usage. Your participation and feedback are most welcome—to submit comments, new entries, or suggestions, contact us today.

# A B C D E F G H I J K L M N O P Q R S T U V W X Y Z
There are 10 names in this directory beginning with the letter R.
Radio Frequency (RF)
Radio waves. This term generally means “wireless communication” when referred to in IoT discussions.
Radio Frequency Identification (RFID)
Generally speaking, this is the use of strong radio waves to “excite” enough current in a small tag to send a radio transmission back. It works over short range and only for small amounts of data.
RADIUS
Remote Authentication Dial-In User Service. RADIUS servers are responsible for receiving user connection requests, authenticating the user, and returning all configuration information necessary for the client to deliver service.
Remote Monitoring and Control
The increasingly automated monitoring and control of devices, technologies, or processes. Wireless devices which send information gathered directly to control centers are often used to achieve this.
Remote Sensing
The use of various technologies to make observations and measurements at a target that is usually at a distance or on a scale beyond those observable to the naked eye.
REST
Representational State Transfer. An architecture for web standards, especially for the HTTP protocol. It is supposed to simplify the design of network applications compared to, for example, SOAP.
RESTful Web Services
Web services that are realized within the REST architecture are called RESTful Web Services. Also see REST.
RF Geolocation
A general term that applies to “finding” a radio transceiver with another. GPS is a good example. A good rule to remember is that to do RF geolocation well, you need a large RF bandwidth.
RF Sensitivity
The minimum magnitude of input signal you need based on a specified signal-to-noise ratio to achieve at minimum error rate.
RFID
Radio Frequency Identification.