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 12 names in this directory beginning with the letter U.
UART
Universal Asynchronous Receiver/Transmitter.
UBI
Usage-Based Insurance.
Ubiquitous Computing
The concept of embedding microprocessors in everyday things so they can communicate information continuously. Ubiquitous devices are expected to be constantly connected. Utility smart meters are an example of ubiquitous computing, replacing manual meter-readers with devices that can report usage and modify power settings on ubiquitous appliances.
Ultra-Wide Band
A “spark gap” transmitter that emits a very weak, very wide (in frequency) pulse of RF energy. This signal is used mostly for localizing signals. Wide signal bandwidths are good for measuring distance.
UMTS
Universal Mobile Telecommunications System.
Uniform Resource Identifier (URI)
The unique identifier that makes content addressable on the Internet by uniquely targeting items, such as text, video, images, and applications.
Uniform Resource Locator (URL)
A particular type of URI that targets web pages so that when a browser requests them, they can be found and served to users.
Universal Asynchronous Receiver/Transmitter (UART)
A microchip controlling a computer’s interface to serial devices, converting the bytes it receives from the computer along parallel circuits into a single serial bit stream. A 16550 UART has a 16-byte buffer.
Universal Authentication
A network identity-verification method that allows users to move from site to site securely without having to enter identifying information multiple times.
Universal Mobile Telecommunications System (UMTS)
Also referred to as 3G cellular technology, this is the third iteration of the GSM. It achieves improved data transfer speeds over 2G by adding additional higher frequency bands (2100MHz).
Uplink
Notified as UL or U/L, this is the process of sending data from your device/computer to a server or target address. In a cellular network, this would be seen as data being sent from a mobile handset to a cellular base station.
Usage-Based Insurance (UBI)
Also called Pay as You Drive (PAYD), UBI bases the insurance rate on pre-defined variables including distance, behavior, time, and place. The data gathering and telematics can be provided by a “black box” in the vehicle, a dongle-type device, or even a smartphone.