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.

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There are 23 names in this directory beginning with the letter D.
Dashboard
A user interface that presents key information in a summarized form, often as graphs or other widgets. Derived from the classic automobile dashboard, the design of the interface depends on what information needs to be monitored or measured.
Data Center
A collective term for the physical site, network elements, systems, etc., that supports computing and network services.
Data Janitor
A subtask of data science concerned with the cleaning up of dirty or duplicative data. Oftentimes the janitor must get data into the correct columns and sort it.
Data Lake
Coined by Pentaho CTO James Dixon, a data lake is a massive data repository, designed to hold raw data until it’s needed and to retain data attributes so as not to preclude any future uses or analysis. The data lake is stored on relatively inexpensive hardware, and Hadoop can be used to manage the data, replacing OLAP as a means to answer specific questions. Sometimes referred to as an “enterprise data hub,” the data lake and its retention of native formats sits in contrast to the traditional data warehouse concept.
Data Scientist
A job that combines statistics and programming, using languages such as R, to make sense of massive data sets. IoT sensors, for example, create mountains of data, and the data scientist’s role is to extract valuable information and detect anomalies.
Data-Driven Decision Management (DDDM)
An approach to business governance valuing decisions that can be backed up with verifiable data.
Datakinesis
A termed coined by Marc Blackmer, datakinesis occurs when an action taken in cyberspace has a result in the physical world. Industrial Control Systems, for example, are vulnerable to datakinetic attacks where physical equipment such as valves and sensors are compromised and damaged by hackers. Stuxnet is one such example.
DDS
Digital Data Storage. This format is used to store computer data on audio tape. It was developed by HP and Sony in 1989 and is based on the digital audio tape (DAT) format and was a widely used technology in the 1990s.
De-identification
The stripping away of personally identifiable information from data prior to its use. The process must include the removal of both direct identifiers (name, email address, etc.) and the proper handling of quasi-identifiers (sex, marital status, profession, postal code, etc.).
Degrees of Freedom (DoF)
An engineering concept used in MEMS that describes the directions in which an object can move and generally the number of independent variables in a dynamic system.
Demand Response (DR)
The voluntary reduction of electricity use by end users in response to high-demand pricing. Demand response can reduce electrical price volatility during peak demand periods and help avoid system emergencies. An example of DR would be a utility paying Nest to have thermostats turn down air conditioners in empty homes on a hot day.
Device Attack
An exploit that takes advantage of a vulnerable device to gain access to a network.
DG
Distributed Generation.
DIN Rail
A metal rail used for mounting electrical equipment and racks.
Distributed Generation (DG)
Decentralized, modular, and flexible power generation located close to the serviced loads. Distributed microgrids can control smaller areas of demand with distributed generation and storage capacity.
DIY
Do It Yourself. Enthusiasts generally tinker with gadgets or software to improve the functionality or do custom-install projects in their homes.
DNP3 Protocol
An open, standards-based protocol for the electric utility industry with interoperability between substation computers, remote terminal units, intelligent electronic devices), and master stations. Groups of enabled things are organized into namespaces.
DoF
Degrees of Freedom.
Domain Model
A model that contains all areas and terms related to a certain field of interest. It includes attributes, relations, constrains, acts, etc., that are relevant for a certain task.
Domotics
A combination of “domestic” and “robotics.” Also a composite of the Latin domus and informatics, domotics includes home automation systems, home robots, whole house audio/visual systems, and security systems. Domotic devices have the ability to communicate with each other.
Downlink
Abbreviated as DL or D/L, downlink is the process of downloading data onto an end node from a server/target address. In a cellular network this would be seen as data being sent from a cellular base station to a mobile handset.
DR
Demand Response.
DWG
A format for different computer-aided design programs, including AutoCAD. It is used to store two and three dimensional design data and meta data.