Visonic- Wireless security, wireless emergency systems, wireless property protection


This glossary contains many of the terms used in the Visonic web site and in the home security industry in general. Please refer to this list or to the Frequently Asked Questions (FAQ) page to find additional definitions of terms and answers to other home security-related questions.


24 Hour Zone

Zone that is continuously active regardless of whether the alarm system is armed or disarmed (can be a panic button or a smoke detector). Most of Visonic's control panels are with 28 zones.


Abort Period

When an alarm is initiated, the internal sounder is activated first for a limited period of time, which is the abort period set by the installer. If an alarm goes off accidentally, it is possible to disarm the security control system within this abort period before the real sirens start and the alarm is reported to the remote responders.

Active Infrared Anti-mask

(See also Anti-mask). This is the most reliable form of anti-mask. It transmits infrared light from the detector and measures the amount of light reflected back. The anti-mask algorithm then analyzes the return signal to determine if the detector's performance has been modified. If attempts are made to mask the detector, the signal changes. See for example Hunter.

Advanced Temperature Compensation

Feature found on all Visonic's advanced PIRs and used to prevent false alarm activations caused by temperature changes. This is done by adjusting the threshold levels on the unit as the background temperature of the room changes.

AES (Advanced Encryption Standard)

AES is a symmetric (private key) encryption that uses a shared secret key between the sender and receiver to encrypt and decrypt data. It was originally published in 1998 and adopted by the U.S. government in 2000. In 2003, the US National Security Agency (NSA) stated that AES was secure enough to protect its information at the secret and top-secret levels. Read more about how PowerG  uses this encryption method.

Alarm Verification

Alarm verification can be achieved using multiple and varied techniques, all of which have the same purpose: to reduce the number of false alarms fed to the police. Previous methods such as monitoring audio microphones at the alarmed premises proved to be somewhat useful in reducing false alarms, but still left the person at the monitoring station with the difficult task of deciding whether an actual crime was in progress. The most recent and promising method of alarm verification uses cameras and optional voice communication equipment at the alarmed premises. This is known as Video Verification.

Anti-disguise mode

Unique mode that further increase the reliability of Visonic PowerMaster systems. It enables detection of an intruder who manipulates his/her body temperature to be very close to the ambient temperature.


Feature used to detect attempts to blind a detector by blocking the detector’s field of view (for example, by placing objects in its field of view or spraying the lens with paint). Masking may be attempted when the security control system is disarmed to allow intruders to enter the premises at a later stage without being detected; or when the system is armed from below the detector itself. See for example the TOWER-10AM.

Audio Verification

Event-activated alarm verification method that provides real-time audio signals from the security system installed in the protected premises to the central alarm station. This enables the monitoring agency to verify whether an activity occurred that warrants an immediate emergency response.


Back Tamper

Microswitch or spring used to detect intruder attempts to pry a unit away from the wall to which it is mounted.


Copying data from the security system to a different device to prevent data loss.

Backward Compatible

Ability of a device to function with previous versions.


The amount of data that can be transmitted in a fixed time period. The unit of measurement differs according to device type (for example, bps for digital devices and Hz for analog devices).

Bypass (Zone)

When Bypass mode is used for specific alarm zones, alerts are not generated when activity is detected in those zones (for example, internal zones such as a kitchen during the day or the first floor of a two-story house at night can be defined as bypass zones).



Type of zone control enabling activity tracking in protected areas when the security system is in a disarmed state. Whenever a chime zone is "opened", the buzzer beeps twice (it does not beep when the zone is "closed"). Residences can use this feature to announce visitors or keep track of children's whereabouts. Businesses can use it to signal when customers enter the premises or track when personnel enter restricted areas.


A protocol that transmits a unique 28-bit (rolling code) ID command, selected from over 100 million possible combinations, to prevent "code grabbing" by potential intruders trying to defeat the home security system. The next time the button is activated, the transmitter sends out a different CodeSecure ID, which is selected by a proprietary code encryption algorithm and can only be recognized by the target receiver.

Control Panel

An electronic panel that is the controlling component in the home security system. The control panel both receives and transmits Radio Frequency (RF) signals from and to the wireless peripherals communicating with it (such as keyfobs, sirens, and safety and intrusion detectors). Acting as the brain of the whole system, the control panel issues alarms and alerts to the monitoring center or a private phone when an emergency occurs.

Creep Zone

With this important security feature, used in most passive infrared detectors (PIRs), the sensor detects activity directly beneath itself, creating a look-down detection zone, and thus preventing an intruder from accessing the secured premises by sneaking directly below the detector. Full creep zone is featured, for example, in TOWER-10AM, TOWER-12AM, TOWER-20AM MCW.

Curtain Lens

Interchangeable lens used to change a beam pattern into a straight vertical coverage, thereby providing full barrier protection. PIRs with this type of lens are ideal for protecting hallways or entry points. See for example, Clip MCW.


DD234 Standard

DD243 is a standard designed to generate confirmed alarms. It also gives recommendations for the design, installation and configuration of intruder alarm systems that incorporate alarm confirmation technology for alarm notification to an alarm receiving center (ARC) for Police Response.

Digital FM (Frequency Modulation) Processing

A smart mechanism that transforms sensor signals into the frequency domain without amplifying them first. This eliminates the need for conventional amplifiers and digital-to-analog converters. The advantages of this frequency modulation method include robustness, accuracy and immunity to noise, which translates into high immunity to false alarms. See for example Next+ PIR MCW.


Detector that uses both PIR and microwave technologies to detect movement. This reduces the amount of false alarms as both technologies need to detect movement for an alarm to be raised. See for example, Duet-AM, Next+ DUO, Discovery Duo, TOWER-12AM.

Duress Code/Alarm

Feature used to send a silent duress signal when the user is being coerced to open the premises.


Elliptic/Parabolic Mirror

Mirror technology patented by Visonic that uses elliptical mirror optics together with unique combined elliptical-parabolic mirror design to create a highly efficient mirror with high optical gain and longer range delivery.


(Electromagnetic interference). Interference caused when the radio waves of one device distort the waves of another. Cell phones, wireless computers and even robots in factories can produce radio waves that interfere with RFID tags.

End-of-Line (EOL) Resistors

Highly-secure type of wiring that allows the control panel to supervise the field wiring for open or short circuit conditions, thereby preventing intruders from tampering with a security control system. In the most advanced detectors, this component is integrated into the detector circuit and is switch-selectable.


Type of local area network (LAN) used for connecting multiple devices. Can be used to connect the home security system and allow for multiple access points in the network.

Event Log

Events registered and stored in the control panel's memory (for example, triggered alarms, arm and disarm events, and AC failures).

Expander Module

Small Printed Circuit Board (PCB) with multiple zones that can be plugged into a panel or used remotely to increase the number of zones on the control panel. See PowerMaxComplete.


Factory Default

The default settings defined for a control panel when it is manufactured. These can be left as is or changed according to specific installation needs.

Frequency Hopping Spread Spectrum (FHSS)

This technology is based on advanced radio technology for secure and reliable message transmission under adverse battle conditions. With FHSS, the bandwidth is divided into multiple channels. Once a wireless connection is established and time-synchronization is gained, the receiver and transmitter agree on one of the practically infinite frequency hopping sequences. These sequences are both encrypted and time-dependent. According to the current time and a mathematical calculation, both the receiver and transmitter jump to the next channel in the sequence at the same time. Read more about how PowerG  uses this technology.

Fresnel Lens

Custom-designed lens used to achieve a very high level of white light rejection, accurate detection and maximum optical gain in the infra-red spectrum. The high optical gain also increases immunity to electronic noise and reduces the number of false alarms.

Front Tamper

Spring or micro-switch used to prevent intruders from removing the security system's front cover and deactivating it.

Full Duplex

Simultaneous transmission of data in two directions (for example, in the case of telephones).


Glass Break Detectors

Detectors activated by the sound of breaking glass. This helps to detect the intruder upon entry into the home (and not after). See Glass-Tech, Glass-Tech AM, MCT-501.


Home Automation

Functions used to remotely or automatically control home appliances (also known as Domotica).


Internal Sounders

Ensure that everyone on the premises can hear an alarm.

Internet Protocol (IP)

Protocol used to deliver packets (datagrams) from a source host to a destination host. Used in home security systems and personal emergency response systems to transmit data, such as video images and health monitoring data, from a control panel to a central server, from where it can be transmitted to a service provider.

IP Address

Unique four-byte numerical identifier for each unit on the Internet or a network. Required for communication over a network.


K-band microwave

The microwave frequency spectrum ranging between 18 and 27 GHz as defined by IEEE. This band minimizes microwave false alarms events since there is less likelihood that they will penetrate walls.



When the home security system is armed in Latchkey mode, the system calls predefined numbers once the system is disarmed. This can be used, for example, to notify parents that their child has returned home and disarmed the home security system.

Liquid Crystal Display (LCD)

Display technology often used on control panel displays and security accessories such as keyfobs. See for example MCT-237.

Look Down Zone

Feature found on some detectors. Includes a lens at the bottom of the detector through which a beam is sent, increasing protection by preventing attacks from underneath the unit. See for example TOWER-20AM MCW.


Microwave Antimask

Uses microwave return signal processing to detect movement of objects used to block a detector's field when the security control system is unset. Anti-mask algorithms are used to evaluate if the detector's performance has been impaired and if so, send a signal (see also Anti-mask and Active Infrared Antimask). See for example Next+ DUO AM.

Mirror Optics

Concave mirror used in some detectors to focus infra-red energy. This gives the highest PIR detection accuracy and increases immunity to electronic noise.


Network Address Translation (NAT)

Internet standard used to create a type of firewall by translating (and thereby hiding) internal IP addresses into a different set of IP addresses for external traffic.


Obsidian Black Mirror

Visonic patented technology for detectors. Uses unique black nickel coating instead of conventional bright "nickelized" mirror to act as a selective optical filter to infrared energy, thereby eliminating white light interference and increasing detection sensitivity. See for example TOWER-10AM, TOWER-12AM, TOWER-40 MCW, TOWER-20AM MCW.

Octa-Quad Technology

A unique, technology patented by Visonic. It is based on an array of eight independent PIR detectors that each monitor 1/8 of the field of view utilizing a Quad configuration and employing Visonic’s patented, market proven TMR™ (True Motion Recognition) algorithm. A central motion processor analyzes the motion signals detected in each of the individual detectors, taking into account the time, amplitude, background temperature, speed of motion, size of target, and the direction of motion. Then, it compares the signals in relation to adjacent detectors and calculates whether a real alarm is justified based on true motion detected consecutively by the array of individual detectors. See for example TOWER-20AM and TOWER-20AM MCW.

Open Circuit

Electrical circuit that requires the closing of a switch in order for current to flow through it (does not flow during normal operation).


Auxiliary devices that are part of the security system and control external devices such as light indicators. Can include transistorized outputs (current-sinking devices) or relay outputs (dry contacts).



Type of zone used with most control panels. Generates an alarm even if the security control system is unset. It is recommended for use when personal emergency response buttons are used with the system.


Used to enable the control of multiple separate alarm areas from a single panel (usually used in shared accommodation such as apartment blocks).

Passive Infrared Detector (PIR)

Standard detector used to detect intruders by sensing their body heat in protected zones.

Perimeter System

Sensing devices placed on exterior surfaces that activate an alarm when triggered (such as door or window magnets, and outdoor detectors).

Periodic Self-test

Feature used to test detector sensors and amplifier chains during periods of alarm inactivity and report in the case of failure.

Personal Emergency Response System (PERS)

A control panel unit connected to the emergency peripherals that signal the unit about emergency situations. These signals are then sent to the monitoring center so that help can be provided. PERS solutions assist caregivers in managing risk and enable vulnerable people to stay independent in a home environment for longer. See Amber PERS systems.

Pet Immune Detector

Detector set to ignore movement caused by animals, to enable protection of premises in which pets or other small animals are likely to be found. See for example Next+ K9-85 MCW.


Programmable output available on most control panels. Acts as a light switch so that if, for example, it is programmed for Bell, it will switch on anything connected to it when the bell box is activated.

Piezo Sounder

Consists of an electronic piezo element used on most external sounders to produce an extremely high-pitched output.


Strong, resilient and partially fire-resistant plastic used for bell boxes and security control system panels.


Visonic proprietary technology for "anti-collision" transmission sequence to ensure that signals transmitted at the same time are acknowledged by the receiver.


Visonic's new proprietary technology, launched in 2010, is the second generation of wireless communication for Visonic's wireless alarm systems and devices. PowerG combines several well-proven technologies to provide the convenience of a wireless network with reliability similar to that of a hard-wired one. Read more about PowerG.


Thermal sensor used in infra-red sensors.


Quad Detector

PIR with four built-in infra-red sensors for increased accuracy and detection. See for example Discovery QUAD, Next QES.


Radio Frequency (RF)

This is a subset of Electromagnetic Radiation and is used more in terms of Radio Energy than actual frequency. Radio Energy properties include good propagation in air, which facilitates RF system communication between different parts of the system (such as the control panel and peripheral devices), without the need for wired connections. RF system communication is used in Visonic's are PowerCode and CodeSecure protocols.

Radio Frequency Immunity (RFI)

Ability to prevent false alarms created by radio waves (resulting from mobile phones, radios etc.) interfering with alarm system electronics.


A device used to extend the communication range between a wireless receiver and a transmitter. For example, in a large residence, a repeater can extend the range between a PowerMax control panel and a magnetic contact (MCT-302 or MCT-320) installed on a balcony door far from the control panel.

Request to Exit (REX)

Indication that someone is leaving a protected area. No card is required for this and it is generated using a device such as a push button or PIR.


Standard interface used to connect serial devices such as modems for distances of between 25 and 100 feet.


Sealed Optics

Isolation of the optical area in a detector, minimizing false alarms caused by elements such as insects and dust.

Selectable Pulse Count

Available via DIL switches or shunts, this feature allows the user to vary detector sensitivity according to each environment.

Solid State Relays (SSR)

Silicon-based, optically isolated MOSFET (metal–oxide–semiconductor field-effect transistor) devices with no moving parts. Used to prevent sticking and increase reliability and security.


Internal monitoring by a wireless control panel of a connected device, such as a detector, keyfob or siren (i.e. monitoring of an active presence of a transmitter and its status) to determine if it is working correctly.


Target Specific Imaging (TSI)

Patented Visonic technology used in motion detectors to reliably distinguish between human bodies and pets weighing up to a specified weight. See for example Next+ K9-85, Discovery K9-80, V-Pet.

Temperature Compensation

Feature found on some PIRs and used to ensure consistent detection capability despite temperature changes and prevent false alarm activations caused by such changes (see also Advanced Temperature Compensation).

Time Division Multiple Access (TDMA)

TDMA is a digital transmission technology that allows a number of users to access a single radio-frequency (RF) channel without interference. By allocating unique time slots to each user within a channel, each time slot acts as a separate communication path. Each user uses only part of the channel capacity, allowing multiple users to share the same radio frequency channel without causing interference. Read more about how PowerG  uses this encryption method.

True Motion Recognition Algorithm

Patented Visonic algorithm that uses parameters such as speed, shape, size, and temperature to detect signals originating from human movement and distinguish them from false alarms. Implemented for example in DUET-AM, Next+ PIR, TOWER-40 MCW and more.

Two way

Ability of a device (for example, X-10 device, siren, etc.) to both transmit and receive commands. For example, two-way devices can send status information following a query received from the control panel. See for example MCT-237, MCS-730 and more.



Ability to program and monitor home security systems and personal emergency response systems using a PC so that installation companies can maintain system definitions remotely. The control panel needs to include a modem to accept the information from the PC.


User's pin code for setting and unsetting the home security system.

User Code

User's pin code for setting and unsetting the alarm system.


Video Verification

Utilizes a customer's digital cameras coupled with broadband transmission to send live video associated with an incoming burglar alarm to the monitoring center. See PowerLink for more information.

V-Slot Technology

Visonic's revolutionary, patented optical design concept for a remarkably small, recessed concave window used in motion detectors. This provides very high resistance to environmental interference and vandalism, while also raising sensitivity. See for example in TOWER-10AM, TOWER-12AM, TOWER-20AM MCW, TOWER-40 MCW.


White Light Protection/Filter

PIR sensor lenses use high-quality white light filtering material to prevent false alarms caused by strong light sources such as sunlight and car headlights.



Power-line wiring carrier protocol for communication between compatible home devices using the existing 240V wiring in the house. Facilitates the remote control of electrical devices from anywhere in the house.


Zone (interior, perimeter, delay, 24-hour, fire, non-alarm, emergency)

Area defined via the control panel that can be activated or deactivated separately from other areas. This means that activity can occur in one zone without activating the alarm in other zones.

Zone Descriptors

Feature available on some control panels that allows for the text name tagging of specific zones (for example, Zone 1 can be tagged as "Kitchen").