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Tankless Water heater

Tankless (or instantaneous or on-demand) water heaters instantly heat water as it flows through the device, and do not retain any water internally except for what is in the heat exchanger coil.

When there is a demand for hot water the tankless water heater's water flow sensor indicates the flow, starts the heating process and sends a signal to the control. Water is heated to the desired temperature as it circulates through the heat exchanger providing continuous hot water.

  Tankless Water Heater

Task Lighting

Lighting directed to a specific area or surface that provides illumination for visual tasks, such as reading, sewing or cooking. It can be provided by recessed and track lighting, portable lighting or pendant lamps. Task lighting should be free of distracting glare and should be bright enough to prevent eyestrain.



Acronym for Transmission Control Protocol/Internet Protocol. TCP/IP is the protocol standard used by the Internet. The IP portioin deals only with packet transmission. The TCP portion enables two hosts to establish a connection, order and exchange of data.



A device comprised of a capacitor and a resistive element providing electrical termination for signals on a given channel type. Almost all networks require a specific type of terminator depending on the channel type.


Three-Way Dimmer

Dimmer that works with a three-way switch for control from two locations; turns on/off and dims at the dimmer, but only turns on/off at the switch.


Three-Way Lamp

Incandescent lamp with two filaments that provides three levels of light when sequentially switched.


Three-Way Switch

Operates a fixture from two locations. Also called a three-pole switch. Also called a “three-pole switch” because it is connected to three wires; “hot” in, “switched” out and a “traveler” to the other three-way switch.



Within the context of Building Automation Systems, a timer is a device that turns lights or other controlled equipment on and off at pre-programmed times.


Toggle or Toggle Switch

Lever used for control as in the common toggle switch or toggle dimmer. A toggle switch is a class of electrical switches that are actuated by a mechanical lever, handle, or rocking mechanism. Toggle switches are available in many different styles and sizes, and are used in countless lighting applications. Most are designed to provide the simultaneous actuation of multiple sets of electrical contacts, or the control of large amounts of electric current voltages. In lighting control applications they can be low or high voltage.


Track Connector

Part that joins sections of electrified track.


Track Lighting

Any lighting system that utilizes individual lamps or lamp housing which operate off a track or strip mounted to the wall or ceiling. Track lighting can provide general, task or accent lighting all at once in a very flexible system. You can move, swivel, rotate and aim the individual fixtures in any direction along the track, giving you the flexibility to change your lighting scheme as the need arises. You can also hang chandelier and pendant lighting fixtures from some types of track.



A transceiver is a device that has both a transmitter and a receiver which are combined and share common circuitry or a single housing.



A device used to raise (step up) or lower (step down) the electric voltage. For example, many halogen ceiling fixtures require a transformer, most commonly hidden in the wall during installation, to function properly. Step down transformers reduce household voltage (120 volts) to low voltage used in accent and landscape lighting. Larger transformers reduce high voltage used for efficient power distribution to safe and flexible household voltage. Input voltage is on the primary tap; output voltage on the secondary tap.

Transport Protocol or Layer

A communications protocol responsible for establishing a connection and ensuring that all dat has arrived safely; defined in layer 4 of the OSI model. Often implies transport services, which includes the lower-level data link protocol that moves packets from node to node.


Wired Transport Protocols




CAN Bus Robust, fault detectin and isolation, content based addressing
Ethernet Star, Tree, Ring, Line In wide use
I2C Bus, and Point to Point Simple and in widespread use for device interconnect, includes address transmission
Powerline Bus Several protocols are competing for acceptance as the industry standard
SDIO Bus, and Point to Point Based on SPI, with optional additional data lines
SPI Bus, and Point to Point Simple and in widespread use for device interconnect, uses separate chip select lines
UART RS233 Bus, and Point to Point In wide use
UART RS485 Bus, and Point to Point In wide use
USB Tree, tree with hubs and Point to Point In wide use, particularly in consumer level products


Trim and Respond

A control strategy that optimizes the setpoint of a source piece of equipment that supplies one or more receiving units - such as an air handler unit supplying zone terminal units with heating, cooling, ventilation, or similar service.

The source unit communicates with receiving units to determine heating, cooling, and other requirements, and then adjusts its setpoint.

For example, if all zones are comfortable and do not request cooling, the AHU will gradually increase (trim) its supply air setpoint. When a zone requests cooling, the AHU responds by dropping its setpoint. The more zones that request cooling, the more it drops the setpoint. The AHU repeats this process throughout the day to keep zones cool, but with a supply air setpoint that is no cooler than necessary.



Recessed fluorescent fixture for use in a suspended ceiling; derived from the words “trough” and “coffer.”


Tungsten-Halogen Lamp

A gas filled tungsten incandescent lamp containing a certain amount of halogens that intensifies the light source. More commonly referred to as “Halogen” lighting.