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 45 names in this directory beginning with the letter S.
SaaS
Software as a Service.
SBC
Single Board Computer.
SCADA
Supervisory Control and Data Acquisition.
SDN
Software-Defined Networking.
SDO
Standards Development Organization.
Sensor
A device used to measure a specific characteristic of the surrounding environment, such as temperature. The use of sensors and actuators to connect things to the physical world is a key component of IoT. A properly implemented sensor ideally should be sensitive only to the characteristic being measured and should not interfere with what’s being measured nor be influenced by other characteristics.
Sensor Analytics
Statistical analysis of data that is created by wired or wireless sensors.
Sensor Fusion
The process of combining and processing the raw data coming out of multiple sensors to generate usable information. For example, because of the quantity of sensors, a NASA un-crewed vehicle on Mars requires sensor fusion to detect if there has been a failure.
Sensor Hub
A technology that connects sensor data and processes them. This way the hub does part of a processors data-processing job.
Serial Peripheral Interface (SPI)
A specification developed by Motorola for use in short distance communication between sensors and microcontrollers such as Arduino. In contrast to the I2C specification, the full-duplex SPI runs at a higher data rate and is appropriate for applications such as Ethernet and memory cards.
Serial Port Profile (SPP)
A hardware profile used with Bluetooth applications that includes custom AT commands and functionality dedicated to wireless data connections and serial cable replacement.
SGSN
Serving GPRS Support Node (see also GGSN).
Shock Sensing
A MEMS concept referring to the detection of sudden impacts at a predetermined level. Typical applications include shut-off sensing, condition monitoring, and tap detection for data entry.
SIGFOX
A low-bandwidth, wireless protocol that offers excellent range and obstacle penetration for short messages, giving a new low-powered and cost-effective wireless transmission medium for IoT and M2M technologies.
Signal Phase and Timing (SPaT)
Refers to communications associated with the operations of signalized intersections. The major components associated with a SPaT application are roadside equipment (RSE) and onboard equipment (OBE). A SPaT-formatted message can be used to convey the current status of a signal at an intersection.
SIM
Subscriber Identity Module. A piece of hardware (the “smart card”) containing account information for a user on a GSM network. The SIM is inserted into a SIM holder in GSM cellular devices.
Single Board Computer (SBC)
A complete, functioning computer with all functions (I/O, processor, memory) located on one board. Popularized by the Raspberry Pi system, SBCs are constructed in direct contrast to traditional motherboards with plug-in cards for functions like graphics and Ethernet.
SMA
SubMiniature version A. A type of connector commonly used with antenna, giving you male and female coaxial cable connectors that connect with a screw head.
Smart Buildings
Buildings that try to minimize costs and environmental impact. This is achieved by connected systems and efficient use of energy through new, automated technology that intelligently responds to certain circumstances (available solar energy, temperature inside the building, etc.).
Smart Car
An automobile that uses technology to support the driver and create a safer traffic environment. Different systems (inside and outside of the car) are connected and communicate with each other to allow intelligent intervention in dangerous situations and more fluid traffic.
Smart Cities
A concept that tries to create a more intelligent city infrastructure by using modern information and communication technologies. Smart cities propose a more flexible adaptation to certain circumstances, more efficient use of resources, higher quality of life, more fluid transportation, and more. This may be achieved through networking and integrated information exchange between humans and things.
Smart Grid
A general term referring to the application of networking capabilities and computer systems to the electric grid. A smart grid would include smart meters at the point of delivery, allowing for real time monitoring of usage and the adjustment of power settings on some appliances.
Smart Home
The networking of household devices and systems through information and communication technology. This way, processes within a home can be monitored and controlled automatically to optimize quality of life, costs, security, and environmental impact. Related to Connected Home.
Smart Meter
An electronic device that measures and displays resource consumption (of water, gas, electricity, etc.) and communicates this information to the resource distributors and managers (such as utilities and municipalities) and even to consumers. This allows for a more efficient distribution, usage, pricing, and control of these resources.
Smartwatch
A wristwatch, generally with a display, that interacts with the wearer and can communicate with a network wirelessly (the device may have a USB connection for charging and other functions). Many smartwatches have MEMS and physiological sensors, such as ECG and skin temperature thermometers.
SMC
Short Message Center.
SMS
Short Message Service.
SMSC
Short Message Service Center.
SOAP
Simple Object Access Protocol.
SoC
System on a Chip.
Social Web of Things
The socialization of the Internet of Things. This is the integration of connected things into our social life. An example would be a TV that not only informs you that your favorite TV show is on in an hour, but also lets you know which of your friends like the show too so you can meet up and watch together.
Software as a Service (Saas)
A subscription-based model where a monthly fee is charged for using software, rather than an upfront purchase. SaaS (also spelled SAAS) and cloud computing can give cash-strapped enterprises and startups access to applications such as email and lead management that might otherwise be too expensive to purchase outright.
Software-Defined Network (SDN)
An approach to networking that decouples control of information flow from the hardware and gives it to a software controller. This allows for less data to travel wirelessly, making it a potential strategy for IoT networks.
Spaced Repetition
A quantified self-concept designed to increase the brain’s retention of knowledge. Available via apps and cloud-based technologies, spaced repetition operates on the theory that there is an optimum time between memorization drills to maximize retention.
SPaT
Signal Phase and Timing.
SPI
Serial Peripheral Interface.
SS7
Signaling System 7.
Steel Collar
Things in the workplace that replace or augment human labor. A “steel-collar workforce” is capable of tirelessly and efficiently performing repetitive tasks or monitoring. Playing off of the terms “blue collar” and “white collar,” the phrase was first coined in the early 1980s referring to a robotic threat to US manufacturing jobs.
STOMP
Simple (or Streaming) Text Oriented Message Protocol. It’s similar to HTTP and allows STOMP clients to communicate with most of the message brokers making it language-agnostic.
Structure Attenuation
The loss in intensity of radio waves through a medium (like radio waves through a brick wall).
Subscriber Identity Module (SIM)
Provided by the Mobile Network Operator, a SIM contains the International Mobile Subscriber Identity (IMSI) and the security parameters to authenticate access to the network.
Supervisory Control and Data Acquisition (SCADA)
An industrial control system typically used for geographically dispersed assets, often scattered over large distances. SCADA is often applied to electrical utilities to monitor substations, transformers, and other electrical assets.
SX1272
First-generation long-range wireless transceiver from Semtech, which introduced a new type of PHY layer modulation. This technology dramatically increases the range of sub-GHz RF communications.
SX1276
Follow on to SX1272 from Semtech, and this part includes frequency coverage for more unlicensed bands worldwide and several modes that increase receive sensitivity.
System on a Chip (SoC)
A single integrated-circuit technology that contains all the necessary circuits and parts for a complete system. A single microchip in a wearable device, for example, could contain an analog-to-digital converter, memory, logic control, I/O, etc.