DIV Security can install high quality intruder alarms in both residential and commercial premises, small or large. We offer a range of insurance-graded, high quality, reliable hard wired to wireless systems.

We specialise in upgrading existing systems removing the need for a completely new installation, as well as fault finding and repairs.
Our engineers are fully qualified to install without any disruption to your property and can therefore fit these systems during the daytime in a busy office environment.

What is intruder or burglar alarm?

Burglar (or intrusion), and safety alarms are electronic alarms designed to alert the user to a specific danger. Sensors are connected to a control unit via low-voltage wiring or a narrowband RF signal which is used to interact with a response device. The most common security sensors are used to indicate the opening of a door or window or detect motion via passive infrared (PIR). New construction systems are predominately hardwired for economy. Retrofit installations often use wireless systems for a faster, more economical installation. Some systems serve a single purpose of burglar or fire protection. Combination systems provide both fire and intrusion protection. Systems range from small, self-contained noisemakers, to complicated, multi-zoned systems with color-coded computer monitor outputs. Many of these concepts also apply to portable alarms for protecting cars, trucks or other vehicles and their contents (i.e., “car alarms”). See also fire protection systems for specific fire system issues. Burglar alarms are sometimes referred to as alarm systems, see burglar alarm control panel for a discussion of hard-wired burglar alarm system design.Burglar alarms (or perimeter detection systems, Perimeter protection, intrusion detection systems and many more terms for the same thing) are divided to two main fields: home burglar alarms and industrial burglar and perimeter intrusion detection.

These types of sensors are designed for indoor use. Outdoor use would not be advised due to false alarm vulnerability and weather durability.

Passive Infrared Detectors
The passive infrared detector (PIR) is one of the most common detectors found in household and small business environments because it offers affordable and reliable functionality. The term passive means the detector is able to function without the need to generate and radiate its own energy (unlike ultrasonic and microwave volumetric intrusion detectors that are active in operation). PIRs are able to distinguish if an infrared emitting object is present by first learning the ambient temperature of the monitored space and then detecting a change in the temperature caused by the presence of an object. Using the principle of differentiation, which is a check of presence or non presence, PIRs verify if an intruder or object is actually there. Creating individual zones of detection where each zone comprises one or more layers can achieve differentiation. Between the zones there are areas of no sensitivity (dead zones) that are used by the sensor for comparison.

Ultrasonic Detectors
Using frequencies between 25 kHz and 75 kHz, these active detectors transmit ultrasonic sound waves that are inaudible to humans. The Doppler shift principle is the underlying method of operation, in which a change in frequency is detected due to object motion. This is caused when a moving object changes the frequency of sound waves around it. Two conditions must occur to successfully detect a Doppler shift event:

There must be motion of an object either towards or away from the receiver.

The motion of the object must cause a change in the ultrasonic frequency to the receiver relative to the transmitting frequency.

The ultrasonic detector operates by the transmitter emitting an ultrasonic signal into the area to be protected. The sound waves are reflected by solid objects (such as the surrounding floor, walls and ceiling) and then detected by the receiver. Because ultrasonic waves are transmitted through air, then hard-surfaced objects tend to reflect most of the ultrasonic energy, while soft surfaces tend to absorb most energy. When the surfaces are stationary, the frequency of the waves detected by the receiver will be equal to the transmitted frequency. However, a change in frequency will occur as a result of the Doppler principle, when a person or object is moving towards or away from the detector. Such an event initiates an alarm signal. This technology is considered obsolete by many alarm professionals, and is not actively installed.

Microwave Detectors
This device emits microwaves from a transmitter and detects microwaves at a receiver, either through reflection or reduction in beam intensity. The transmitter and receiver are usually combined inside a single housing (monostatic) for indoor applications, and separate housings (bistatic) for outdoor applications. By generating energy in the microwave region of the electromagnetic spectrum, detector operates as an active volumetric device that responds to:

A Doppler shift frequency change.

A frequency phase shift.

A motion causing reduction in received energy.

Photo-Electric Beams
Photoelectric beam systems detect the presence of an intruder by transmitting visible or infra red light beams across an area, where these beams maybe obstructed. To improve the detection surface area, the beams are often employed in stacks of two or more. However, if an intruder is aware of the technology presence, it can be avoided. The technology can be an effective long-range detection system, if installed in stacks of three or more where the transmitters and receivers are staggered to create a fence-like barrier. Systems are available for both internal and external applications. To prevent a clandestine attack using a secondary light source being used to hold the detector in a sealed condition whilst an intruder passes through, most systems use and detect a modulated light source

Glass Break Detectors
The glass break detector may be used for internal perimeter building protection. When glass breaks it generates sound in a wide band of frequencies. These can range from infrasonic, which is below 20 Hertz (Hz) and can not be heard by the human ear, through the audio band from 20 Hz to 20 kHz which humans can hear, right up to ultrasonic, which is above 20 kHz and again cannot be heard. Glass break acoustic detectors are mounted in close proximity to the glass panes and listen for sound frequencies associated with glass breaking. Seismic glass break detectors are different in that they are installed on the glass pane. When glass breaks it produces specific shock frequencies which travel through the glass and often through the window frame and the surrounding walls and ceiling. Typically, the most intense frequencies generated are between 3 and 5 kHz, depending on the type of glass and the presence of a plastic interlayer. Seismic glass break detectors feel these shock frequencies and in turn generate an alarm condition.

Smoke, Heat, and Carbon Monoxide Detectors
Most systems may also be equipped with Smoke, Heat, and/or Carbon Monoxide Detectors. These are also known as 24 hour zones(Which are on at all times). Smoke Detectors and Heat Detectors protect from the risk of Fire and Carbon Monoxide Detectors protect from the risk of Carbon Monoxide.

Alarm connection and monitoring

Depending upon the application, the alarm output may be local, remote or a combination. Local alarms do not include monitoring, though may include indoor and/or outdoor sounders (e.g. motorised bell or electronic siren) and lights (e.g. strobe light) which may be useful for signaling an evacuation notice for people during fire alarms, or where one hopes to scare off an amateur burglar quickly. However, with the widespread use of alarm systems (especially in cars), false alarms are very frequent and many urbanites tend to ignore alarms rather than investigating, let alone contacting the necessary authorities. In short, there may be no response at all. In rural areas (e.g., where nobody will hear the fire bell or burglar siren) lights or sounds may not make much difference anyway, as the nearest responders could take so long to get there that nothing can be done to avoid losses.

Remote alarm systems are used to connect the control unit to a predetermined monitor of some sort, and they come in many different configurations. High-end systems connect to a central station or responder (eg. Police/ Fire/ Medical) via a direct phone wire (or tamper-resistant fiber optic cable), and the alarm monitoring includes not only the sensors, but also the communication wire itself.
False Alarm


A false alarm, is the phone report of an emergency, causing unnecessary panic and/or bringing resources (such as fire engines) to a place where they are not needed. Over time, repeated false alarms in a certain area may cause occupants to start to ignore all alarms, knowing that each time it will probably be a fake. In addition, false alarms have the potential of diverting emergency responders away from legitimate emergencies, which could ultimately lead to loss of life.

The term “false alarm” is actually a misnomer, and is regularly replaced by the term “nuisance alarm.” When a sensor operates, it is hardly false, and it is usually a true indication of the present state of the sensor. A more appropriate term is nuisance, indicating that the alarm activation is inconvenient, annoying, or vexatious. A prime example of this difference is burglar alarms being set off by spiders. (A spider crawling on a web in front of the motion detector appears very large to the motion detector.)

One tragic example of the consequences of continued false alarms was at Boland Hall at Seton Hall University on Months of false alarms caused many students to start ignoring the fire alarms. However, when an actual fire broke out, three students who ignored the alarms died, and many others suffered injuries.

We can provide wireless and hard-wired intruder alarm installation for both domestic and commercial premises, also offer maintenance and repair service which is available 24 hours throughout the whole year.


To book your free security survey fill out a Contact Us form.

24/7 Emergency intruder alarm repair service available.

Alarm systems are a worthwhile investment in the protection of your home and family.

D.I.V. Security Systems offer a range of high quality, reliable hard wired and wireless systems, for both domestic  and commercial premises.

We specialise in intruder alarm repairs and fault fining, providing a real 24/7 emergency call out service covering a wide range of intruder alarm systems.

Intruder alarm system installation.

The type of alarm  depends on your preferences, and the level of protection you require.

A key consideration is what you would prefer to happen when your alarm goes off. Bells-only alarms make a noise, but do not contact anyone (such as the police or the homeowner). Speech diallers, a device can be fitted inside an alarm, automatically contacts you or other nominated friends and family when the alarm is triggered. Alternatively, you could get a monitoring contract, whereby you would pay an annually monitoring charge to a security company to take action or call the police if the alarm goes off.

Monitoring costs vary between the different signalling types.

Wireless intruder alarm installation, maintenance.

Alarms can be either wired or wireless. Wireless systems provide a more streamlined installation and can be used in places where wired systems can’t, and can be removed more easily if you move house. They use battery-powered sensors that communicate with a control panel using radio signals.

Wireless intruder alarm maintenance costs are slightly higher, due to sensor batteries need to be replaced periodically.

Hard wired intruder alarm installation and maintenance.

Hardwired systems have an edge on reliability, lower maintenance cost, while installation takes longer, and sometimes cause more disruption.