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Glossary of Terms

An incomplete list of terms in our industry.


Ad Hoc

The two devices communicate through an ethernet cable or wireless cards.


Networking devices that divide up the network into different segments to manage the amount of traffic. This prevents unnecessary traffic from entering other parts of the network and reduces congestion. As a network becomes more complex, bridges make sure your network speed doesn't drop dramatically.


Crosstalk is a type of noise signal that corrupts the actual signal while transmission through the communication medium. Crosstalk occurs when a signal transmitted on one cable interferes and corrupts the signal transmitted on another cable in close proximity. 

Double Pole Double Throw (DPDT)

DPDT switch is a switch that has 2 inputs and 4 outputs; each input has 2 corresponding outputs that it can connect to.Each of the terminals of a double pole double switch can either be in 1 of 2 positions. This makes the the double pole double throw switch a very versatile switch. With 2 inputs, it can connect to 4 different outputs. It can reroute a circuit into 2 different modes of operation.

Digital Signal Processing (DSP)

The use of digital processing, such as by computers or more specialized digital signal processors, to perform a wide variety of signal processing operations.

Dual tone multi-frequency (DTMF)

The sounds or tones generated by a telephone when the numbers are pressed.

Full Duplex (FDX)

FDX switches allow for the simultaneous transmission of information between the switch and the endpoint.

Foreign Exchange Subscriber (FXS)

FXS is the port that actually delivers the analog line to the subscriber. In other words, it is the “plug in the wall” that delivers a dial tone, battery current and ring voltage. This is the jack or interface to the phone system which FXO devices can be connected to.

Foreign Exchange Office (FXO)

FXO is the port that receives the analog line. It is the plug on the phone or fax machine or the plug(s) on your analog phone system. It delivers an on-hook / off-hook indication (loop closure). Since the FXO port is attached to a device, such as a fax or a phone, the device is often called the “FXO device.” This port establishes the connection to the analog line.


An interconnection permitting passage of current between two or more electric utility systems

Power over Ethernet (PoE)

A technique for delivering DC power to devices over copper Ethernet cabling, eliminating the need for separate power supplies and outlets.

Public Switched Telephone Service (PSTN)

PSTN refers to the traditional backbone of telecommunication across the globe. While today’s communication network has seen a digital shift, the PSTN historically made use of underground copper wires and telephone lines to connect people and businesses.


A device that receives electronic signals, cleans them and re-transmits them at a higher power level. Signals transmitted over cable tend to degrade over long distances. Repeaters are needed so that the signal can travel longer distances.

Radio over IP (RoIP)

In a nutshell, RoIP is Push-to-Talk (PTT) communication over the internet. RoIP stands for Radio over IP (Internet Protocol) which simply means the radio signals are transmitted via internet connection to increase their range and reliability.

Recommended Standard 232 (RS-232)

A standard originally introduced in 1960[2] for serial communication transmission of data. It formally defines signals connecting between a DTE (data terminal equipment) such as a computer terminal, and a DCE (data circuit-terminating equipment or data communication equipment), such as a modem.

Session Initiation Protocol (SIP)

SIP is a protocol used in VoIP communications, allowing users to make voice and video calls

Server Name Indication (SNI)

An addition to the TLS encryption protocol that enables a client device to specify the domain name it is trying to reach in the first step of the TLS handshake, preventing common name mismatch errors.

Single Pole Double Throw (SPDT)

A switch that only has a single input and can connect to and switch between 2 outputs. This means it has one input terminal and two output terminals. A Single Pole Double Throw switch can serve a variety of functions in a circuit. It can serve as an on-off switch, depending on how the circuit is wired. Or it can serve to connect circuits to any 2 various paths that a circuit may need to function in. For example, a SPDT switch can connect to create a Ready Mode and a Standby Mode in a printer.

Transport Layer Security (TLS)

A security protocol that provides privacy and data integrity for Internet communications.

Volt Direct Current (VDC)

Direct current is the type of current that comes from a battery or the power supplies of many electronic devices. Direct current flows at a constant rate in a constant direction. Direct current provides a stable voltage for sensitive electronics.

Voice over IP (VoIP)

Voice over Internet Protocol is a technology that allows users to make and receive phone calls over the internet.

Voice Operated Switch (VOX)

A switch that operates when sound over a certain threshold is detected. It is usually used to turn on a transmitter or recorder when someone speaks and turn it off when they stop speaking. It is used instead of a push-to-talk button on transmitters or to save storage space on recording devices.


The XLR connector is a type of electrical connector primarily found on professional audio, video, and stage lighting equipment. The connectors are circular in design and have between three and seven pins. They are most commonly associated with balanced audio interconnection, including AES3 digital audio, but are also used for lighting control, low-voltage power supplies, and other applications.

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