Burglar Alarm Systems

Every burglar alarm system has a few main parts: the control panel, the brain of the system, which monitors the zones and makes the decisions; a keypad, remote control or mobile app for arming and disarming; detectors such as PIR motion detectors, door and window magnetic contacts, glass-break sensors and shock sensors; indoor and outdoor sirens, usually with a strobe light; and a communicator (dialer) that reports events over a landline, the mobile network or the internet. A power supply with a backup battery keeps all of these parts working during a power cut. Each detector is connected, by cable or by radio, to a zone, that is, a numbered input on the panel, and the panel decides from the zone type and the arming state whether a change on that zone counts as an alarm.

A wired system is the most robust option: the detectors have no batteries to replace, they are immune to radio interference and jamming, and with end-of-line (EOL) resistors the panel also detects a cut or shorted cable, so it is the first choice for new buildings or renovations where cable can be run in conduit. A wireless system installs quickly and without damage in finished homes and offices, and detectors are easy to move, but each detector's battery typically has to be replaced every 2 to 5 years, the radio range must be tested on site, and the system should be two-way and supervised so that a lost detector or jamming is reported. For many projects the best answer is a hybrid panel: wired detectors wherever cabling is easy and wireless ones for points that are hard to reach with cable. KDT's KB-M2 panel is hybrid, with 6 wired zones on board, expandable to 192, and support for up to 100 two-way 868 MHz wireless devices.

Design in layers: first the perimeter, that is, a magnetic contact on every door, window and balcony door that can be reached; then the interior, that is, PIR detectors on the routes an intruder has to take, such as the hallway and the living room; and finally point protection for a safe or a valuables cabinet. List every possible way in, including balconies, roof hatches, skylights and walls shared with a neighbouring unit, and give each detector its own zone so you know exactly which point was triggered. As a typical example, a 100 to 120 m² apartment needs a magnetic contact on the entrance door, 3 more on balcony doors and reachable windows, 3 PIRs and a smoke detector, plus a keypad by the entrance and an indoor siren: that is 8 zones, and with about 25% spare for later additions, 8 × 1.25 = 10, so choose a panel with at least 10 zones.

Install the keypad inside the protected area near the main entrance, on the entry route, so it can be reached within the entry delay, and where it cannot be seen from outside through glass. Install the control panel somewhere else, out of sight, for example in a closet or a plant room, inside the coverage of a detector and close to power and the network, so that an intruder cannot find and smash it during the entry delay. Mount the outdoor siren as high as possible on a wall that can be seen from the street, typically 3 m or more, so it cannot be reached without a ladder, and put the indoor siren where it cannot quickly be reached and silenced, for example high on a hallway wall. If the panel uses the mobile network, check the signal strength at that exact spot before the final installation.

An instant zone raises the alarm immediately when the system is armed and is used for windows and points that are not on the entry route. A delay zone, usually the main entrance door, starts the entry delay so the user can reach the keypad, and a follower zone, such as the PIR in the hallway between the door and the keypad, is normally instant unless the entry delay has already started. A 24-hour zone is active even when the system is disarmed and is used for tamper circuits, safes and technical sensors such as water leak detectors; the panic zone is also 24-hour and can be set to sound the siren or to be silent (only sending messages). A fire zone for smoke detectors is always active too and is signalled with a different siren pattern and report, so that it is not mistaken for a burglary.

Most detectors have a normally closed (NC) alarm contact that opens on alarm, so a cut wire also raises the alarm; a normally open (NO) contact closes on alarm, and a cut wire on it goes unnoticed unless a resistor is in the circuit. An end-of-line (EOL) resistor, fitted at the far end of the run inside the last detector and not at the panel terminals, lets the panel measure the loop resistance and tell normal from an open circuit and from a short circuit, so a zone can be defeated neither by cutting nor by shorting its wires without being noticed. With two resistors (DEOL), the same pair of wires also lets the panel tell an alarm from a tamper. The resistor value (for example 1, 2.2, 4.7 or 5.6 kΩ) depends on the panel model, so follow that panel's manual.

The exit delay is the time you have to leave after arming, and the entry delay is the time you have after opening the entrance door to disarm at the keypad before the siren sounds; during both, the keypad usually beeps. Typical settings are 30 to 60 seconds for exit and 15 to 45 seconds for entry: long enough to walk calmly from the door to the keypad, but as short as possible so an intruder does not gain extra time. Only the entry route (the entrance door and the follower detectors along it) should be delayed, and windows and all other points should stay instant. Some panels can also end the exit delay as soon as the entrance door is closed.

Away (full arming) activates every zone and is for when everyone has left. Stay (partial or perimeter arming) activates only the doors, windows and other perimeter points and automatically bypasses the interior motion detectors, so the occupants can move around freely while any attempt to get in still raises the alarm; on many panels the entry delay can also be removed in this mode. Night is a customised Stay mode that, for example, arms the ground floor and the living room while leaving the route from the bedrooms to the bathroom free. KDT's KB-K2-W keypad and KB-R2 remote control both support full arming, partial (Stay) arming, disarming and SOS.

Partitioning divides one panel into several independent alarm systems, each with its own zones, users and arming state, so one part can be armed while another is in use. Typical examples are a shop on the ground floor with a home above it, the units or floors of an office, the main house and the caretaker's quarters of a villa, or a company's warehouse and office, all managed by one panel and one communicator. Each user code can be limited to the partitions it may operate, and events are reported with the partition number. KDT's KB-M2 panel supports up to 32 independent partitions.

User codes arm and disarm the system, the master code belongs to the owner or manager and is used to add and delete users, and the installer code opens the technical programming menu. Give each person their own code so the event log shows who armed or disarmed the system and when, and delete a code as soon as its owner should no longer have access, for example when a member of staff leaves. Use 4- to 6-digit codes, preferably 6 digits, avoid simple combinations such as 1234, repeated digits or years of birth, and change the panel's default codes on the first day. Choose a keypad with protection against code guessing, such as KDT's KB-K2-W; the KB-M2 panel supports up to 32 user codes.

A duress code is a special code for when someone forces you to disarm the system: the panel disarms exactly as usual so the attacker notices nothing, but it silently sends a duress alarm to the chosen phone numbers or the monitoring centre. Depending on the panel, it is either programmed separately or is a modified form of the user's own code. It is only useful if the people who receive the message know in advance that it means real danger and that they must alert the police rather than call the user. KDT's KB-K2-W wireless keypad supports a duress code.

Tamper protection guards against sabotage: a small switch inside the panel, detectors, keypad and sirens is triggered when the cover is opened and, on many models, when the device is pulled off the wall, and on wired zones with end-of-line (EOL) resistors a cut or shorted cable is also reported as tamper. Outdoor sirens with their own internal battery can also sound by themselves if their cable is cut or they are torn off the wall. Because sabotage can happen at any time, tamper is usually a 24-hour function that is reported even when the system is disarmed, often sounding the indoor siren as well; so before opening any device, for example to replace a battery, put the panel into service mode with the installer or master code as its manual describes. If tamper messages keep appearing without anyone touching the device, usually a cover is not closed properly, the device is loose or there is a cable fault.

Most wall-mounted PIRs are designed for a mounting height of about 2 to 2.4 m (check the datasheet; KDT's KB-P1, for example, is specified for 2 to 2.2 m and, like the KB-PI2-W, covers up to 12 m at 110°) and are usually installed in a corner of the room facing inwards. A PIR is most sensitive to movement across its field of view and least sensitive to someone walking straight towards it, so aim it so that an intruder's likely path crosses its beams. Do not point it at a sunny window, a heater, a radiator, an evaporative cooler or air-conditioner outlet, a fireplace or curtains that move in a draft, and remember that a PIR cannot see through glass, furniture or shelves. After installation, check the coverage with a walk test.

A PIR does not detect heat as such but the contrast between the infrared radiation of a person, whose skin surface is typically around 30 to 34 °C, and the background; when the room temperature gets close to that, as in a space without cooling in summer, the contrast, and with it the detector's sensitivity, drops sharply. Good detectors partly offset this with temperature compensation, but in spaces that get hot, such as warehouses, rooftop rooms or shops without cooling, do not rely on PIRs alone. Protect doors, windows and roller shutters with magnetic contacts and shock sensors, which do not depend on body heat, aim the PIRs so that the intruder's path crosses their beams rather than heading straight at them, and repeat the walk test in the hottest season of the year.

Pet-immune detectors use a special lens and signal processing to ignore animals up to a rated weight, typically 15 to 40 kg depending on the model (for example up to 35 kg on KDT's KB-PI2-W and KB-PO1-W), but only when they are mounted at the specified height and upright, without tilting down. The rating assumes the animal stays near the floor: a cat that jumps onto a sofa back, a shelf or stairs close to the detector enters the human detection zone and may trigger it, and several animals moving together may be seen as one larger body. Do not aim the detector at stairs or furniture the animal climbs on, and if the animal is heavier than the rating or climbs a lot, leave that space out of the armed zones and protect the perimeter with magnetic contacts instead.

A dual-tech detector combines a PIR sensor with a microwave (Doppler radar) sensor, typically at 10.525 GHz, and raises an alarm only when both detect movement within a short time. Because heat sources and sunlight fool only the PIR, while moving objects or movement behind thin walls fool only the microwave, the combination sharply reduces false alarms; the two are also complementary, since microwave is most sensitive to movement towards the sensor, exactly where the PIR is weakest. It is worth using in warehouses, car parks, workshops, rooms with heaters, strong drafts or direct sunlight, and outdoors; KDT's KB-PO1-W outdoor detector is dual-technology. When installing, adjust the microwave range so that it does not reach far beyond the protected space, because microwaves pass through glass and thin walls.

A curtain detector has a very narrow detection pattern, for example 15° on KDT's KB-PC1-W, and instead of covering the whole room it creates a thin, invisible 'curtain' along a window, a glass wall, a door or a corridor. It is used to protect openings while people move freely inside, for example in Stay mode at night, and wherever a wide-angle PIR would also cover areas that must stay free. It is mounted beside or above the opening (the KB-PC1-W at a height of 2.4 m on a wall with a range of 12 m, or at 3.6 m on a ceiling with a range of 8 m), and outdoor versions are mounted under the eaves or along a wall.

Yes, but only with detectors designed for outdoor use, which have a housing protected against water and dust (for example IP54 on KDT's KB-PO1-W) and use two technologies or two PIR sensors to reduce false alarms from sun, rain, plants moving in the wind and small animals. Aim them so that their coverage stays inside your property and does not reach the street, moving trees or the neighbour's yard, and mount them at the specified height, for example 2.2 m for the KB-PO1-W, which covers 16 m at 90°. Outdoor detection gives a warning before an intruder reaches the building, but because the risk of false alarms is higher, it is usually set to send a notification, switch on lights or a camera, or give a short audible warning, leaving the full alarm to the perimeter and interior detectors.

Fix the switch part on the frame and the magnet on the moving leaf, facing each other and on the opening side rather than the hinge side, so the circuit opens with the smallest movement of the door; with the door closed, the gap between the two parts must be well within the contact's maximum operating gap (for example 20 mm for KDT's KB-MG1-W). Steel doors and frames weaken the magnetic field and reduce the operating gap, so use contacts made for steel doors or mount the parts on a non-magnetic spacer. Flush contacts hidden inside the frame are harder to find and defeat than surface-mounted ones, and for high-risk sites there are high-security contacts that also detect an external magnet being used to fool them. Check regularly that the parts have not loosened or shifted, because a misaligned magnet is a common cause of false alarms and of a 'zone open' message when arming.

Both protect the perimeter and raise the alarm while the intruder is still trying to get in, so they can stay armed while people are inside. An acoustic glass-break detector listens for the sound pattern of breaking glass, a low-frequency thud followed by high-frequency shattering, and one detector can cover several windows of a room within its range, typically about 6 to 9 m, provided it has a direct line of sight to the glass and heavy curtains do not block the sound. A shock sensor is mounted on the frame, the glass or the wall and detects the impacts and vibration of breaking, drilling or forcing before anyone gets in, which makes it useful for roller shutters, shared walls, safes and ATMs. Set the sensitivity carefully so that passing traffic, slamming doors or thunder do not cause false alarms, and test glass-break detectors with a glass-break simulator, not by breaking glass.

For the shutter, use a heavy-duty, floor-mounted shutter contact designed for the larger gap and the rattling movement of a shutter, and add shock (vibration) sensors on the shutter or on walls and ceilings shared with neighbours, because shops are often entered through a wall, the ceiling or an adjoining unit rather than the front. Cover the sales floor and the storeroom with PIRs, install a panic button by the cash desk if needed, and put an outdoor siren with a strobe high above the shop front. Because a phone line can be cut outside the shop, use a mobile (4G) or dual-path communicator, and choose the backup battery so that the system keeps working through long power cuts.

Outdoor sirens are typically about 100 to 120 dB at 1 m and indoor sirens about 85 to 110 dB; KDT's KB-SO1-W wireless outdoor siren, for example, can be set to 80, 95 or 105 dB at 1 m, and its specifications list compliance with EN 50131-4, the standard for warning devices. In the open, the sound level falls by about 6 dB each time the distance doubles, so a siren that gives 110 dB at 1 m gives about 90 dB at 10 m and about 84 dB at 20 m; that is why the outdoor siren should be mounted high and facing the street, and a strobe shows neighbours and the police which building is in alarm. The siren time is usually programmed between 3 and 15 minutes so that it does not sound endlessly. On many systems the strobe keeps flashing after the siren stops until the system is disarmed, so the owner can see on arrival that an alarm has occurred.

Yes, preferably. A self-powered outdoor siren has its own rechargeable battery and tamper switches, so it still sounds if the panel is smashed, the mains fail or the siren cable is cut, and it usually raises an alarm by itself if someone tears it off the wall or opens the cover; a siren without a battery goes silent as soon as its cable is cut. Its battery must be kept charged from the panel or a power supply, normally at 12 V, and, like any backup battery, replaced every few years. KDT's KB-SO1-W wireless outdoor siren, for example, runs from a 12 V DC supply and has a built-in 1000 mAh battery that keeps it working for up to 24 hours in standby during a power cut.

Wireless alarm devices usually work in the licence-exempt short-range device bands around 433 MHz or 868 MHz (the exact rules depend on the country); at low transmit power, these sub-gigahertz bands pass through walls and floors better than 2.4 GHz Wi-Fi, and the 868 MHz band is generally less crowded than 433 MHz, which is also used by garage-door and car remotes. In a one-way system the detector only transmits and never knows whether the panel received its message, while in a two-way system the panel confirms every message, the detector resends if needed, and the panel can show the arming state on the keypad or remote and change detector settings remotely. The frequency matters less than the protocol: for reliability, look for two-way communication, supervision, encryption and jamming detection. KDT's KB-M2 panel and its Rhenium wireless devices use two-way FSK communication in the 868 MHz band.

In a supervised system every wireless device sends a periodic 'I am alive' message, and if the panel does not receive it for longer than the set time, it reports that device as missing, so a detector that has been removed, has a dead battery or is out of range does not silently leave a gap in the protection. Devices also report a low battery early enough for a planned replacement, and report an opened cover as tamper. The panel monitors the radio channel and reports continuous interference as jamming, which you should set to send a notification. Encryption and rolling codes prevent a recorded signal from being replayed to disarm the system; KDT's KB-K2-W wireless keypad, for example, uses 128-bit AES encryption and frequency hopping.

The range in datasheets is measured in open space with a clear line of sight, for example 400 to 800 m for KDT's Rhenium wireless devices, depending on the model; inside a building, every concrete wall, reinforced concrete floor, metal door, lift shaft or foil-backed insulation absorbs part of the signal, so the real range is only a fraction of that figure. Before the final installation of each device, check the signal strength at that exact spot with the system's signal test and leave a good safety margin, because a weak link that works on installation day may drop when furniture is moved or a door is closed. Install the panel in the middle of the building rather than in a corner or inside a metal cabinet, and do not mount detectors directly on metal surfaces.

Typically 2 to 5 years, depending on how often the device transmits (how many times a day it is triggered), the supervision interval, the ambient temperature and the battery type; for example, the battery life of KDT's KB-PI2-W detector and KB-MG1-W magnetic contact is rated at up to 5 years on one CR123A lithium battery with 10 triggers a day, and that of the KB-K2-W keypad at up to 3 years on 4 AA batteries. To save battery, many wireless PIRs do not send a new report for a set time after each detection (on the KB-PI2-W this detection interval is adjustable from 30 to 180 seconds, 60 seconds by default), so do not be surprised if a detector does not report twice in a row during a walk test. As soon as the panel reports a low battery, replace it only with the type specified in the datasheet, and it is best to replace the batteries of all detectors at a site in the same service visit.

Detectors are usually wired with 4-core alarm cable (two cores for the 12 V supply and two for the alarm contact), or 6-core when the tamper is wired separately, with a typical conductor size of 0.22 mm², which has a resistance of about 8 Ω per 100 m per core. The voltage drop equals the current times the loop resistance: a detector drawing 25 mA at the end of a 100 m run (16 Ω loop) loses only 0.4 V, but a siren drawing 1 A at 50 m (8 Ω loop) loses about 8 V and will not work, so sirens and long power runs need thicker cable, for example 1.5 mm², which in the same example loses only a little over 1 V. Run alarm cable in its own conduit away from mains cables, and fit the end-of-line (EOL) resistors at the detector end as the panel requires.

Capacity (Ah) = (standby current × standby hours) + (alarm current × alarm time in hours), plus a margin of about 25% for battery ageing and temperature. Example: if the panel, keypad, detectors and communicator draw 350 mA in total and you want 12 hours of standby, that is 0.35 A × 12 h = 4.2 Ah; if the sirens draw 1.2 A in alarm and sound for 15 minutes, they add 1.2 A × 0.25 h = 0.3 Ah; the total of 4.5 Ah × 1.25 ≈ 5.6 Ah, so a standard 12 V 7 Ah battery is the right choice. Measure the currents or take them from the datasheets, and do not forget the keypad backlight and the average consumption of the cellular module. A 12-hour standby is a common design target, and standards such as EN 50131-6 set minimum standby times that depend on the security grade; in areas with long power cuts, however, size the battery for 24 hours or more.

The panel switches to its backup battery automatically with no break in protection, and usually reports the mains failure after a programmable delay so that short outages do not cause needless messages; later it also reports a low battery. How long it keeps running depends on the battery capacity and the total load (see the backup battery calculation), and many panels disconnect the battery when it reaches its cut-off voltage to prevent deep discharge. Remember that the internet modem and router also need power: if they are not on a UPS, the internet path goes down with the mains and only the mobile network path (SMS, calls and data) keeps working. KDT's KB-M2 panel is powered from the mains or PoE and has an internal battery that keeps it running during a power cut; if you power it over PoE, put the PoE switch on a UPS as well.

The main paths are a dialer on a landline (PSTN), the mobile network (GSM/4G) for SMS, voice calls and data, and the internet over Ethernet or Wi-Fi for app notifications and remote control. A landline is cheap but can be cut outside the building, so the panel should at least detect a line cut; the mobile path does not depend on the building's wiring but needs an active SIM card with enough credit and good coverage where the panel is installed; and the internet path is fast and carries the most information, but depends on the modem, its power supply and the internet service. No single path is completely reliable, so for important sites use two independent paths, typically mobile plus internet, and choose a 4G (LTE) module, because 2G and 3G networks are being switched off in many countries.

App notifications are fast, free and detailed, showing the zone name, the partition and the type of event, but they only arrive when both the panel and the phone have internet access, and phone settings such as battery saving, silent mode or disabled notifications can delay or hide them. For important alarms such as burglary, panic and fire, it is better to also send SMS and, even more importantly where the panel supports them, voice calls, which make the phone ring even without internet. Put at least two or three people on the list and test every month that all channels really reach the recipients. KDT's KB-M2 panel can send SMS reports, with custom event filters, to up to 8 phone numbers and be managed with a mobile app.

Check the SIM card first: its credit and validity must not have run out, it must be a voice and SMS plan (a data-only SIM is not enough), and its PIN lock must be switched off; the easiest test is to put the SIM in an ordinary phone and send an SMS from it. Then check the signal strength at the panel's exact location, because a panel inside a metal cabinet, a basement or a plant room often gets a weak signal, and the antenna must be outside any metal enclosure. Enter the phone numbers in the format the panel's manual asks for (for example with a leading 0 or with the country code) and make sure the event you are testing is included in the panel's report filters. If the panel only has a 2G or 3G modem and your operator has switched that network off, you need a 4G module.

Each of these attacks has a countermeasure, but no system is 100% proof against a professional with enough time, so the aim is that any interference is detected quickly and reported. A power cut is covered by the backup battery; a cut phone line, internet or mobile network by using two independent reporting paths (for example mobile plus internet) with a communication-fault report when a path is lost; and jamming of wireless detectors by two-way, supervised devices that report a missing detector or interference. Even if every reporting path is cut, the alarm logic and the siren on the panel keep working by themselves, provided the panel and the siren have tamper protection and a battery and the panel is hidden within the coverage of a detector. For that reason, send fault and tamper events to the same phones as alarms, and put the modem and router on a UPS.

EN 50131-1, the European standard for intrusion and hold-up alarm systems, defines four security grades according to the likely intruder: Grade 1 (low risk: an intruder with little knowledge of alarm systems and simple tools), Grade 2 (low to medium risk: some knowledge and a general range of tools and portable instruments; typical for homes and small businesses), Grade 3 (medium to high risk: an intruder familiar with alarm systems and with a comprehensive range of tools and portable electronic equipment; typical for jewellers, high-value stores and many commercial sites) and Grade 4 (high risk: an intruder able to plan an attack in detail, with means to substitute system components; for very high-security sites). A system, or a part of it, takes the grade of its lowest-graded component, so a Grade 2 detector in a Grade 3 system makes that part Grade 2. Higher grades require more, for example detection of masking of detectors (anti-masking), stricter tamper protection, longer battery standby and more secure signalling. The standard also defines four environmental classes, from indoor to outdoor, which must match where each device is installed.

Most false alarms are caused by user error and installation rather than faulty equipment: a wrong code, forgetting the exit or entry delay, a window left open, a pet in an armed area, a PIR facing a heater, a sunny window or a cooler outlet, a loose magnet, curtains or balloons moving in a draft, insects on the lens, and weak batteries or poor cable joints. The remedies are training every user, setting suitable delays, choosing pet-immune or dual-technology detectors where needed, following the mounting rules, using end-of-line (EOL) resistors and replacing batteries promptly when the panel warns. Most panels can limit how many times one zone can trigger in each armed period (swinger shutdown), and alarm verification also helps: sequential confirmation, where two different detectors must trigger within a set time, or looking at the camera images before anyone is sent to the site. After every false alarm, check the panel's event log to find the zone and the cause, rather than simply bypassing that zone.

Most panels refuse to arm, or warn before arming, while a zone is open, for example a door or window left open or a PIR still seeing movement, or while a tamper is active; close the zone or, if it is really necessary, bypass it for that arming only, knowing that the point is then unprotected. The trouble indicator shows faults such as mains failure, a low or faulty battery, a missing wireless device, a communication fault (no SIM card, no signal, internet or phone line down), a tamper or a clock that has not been set, and the keypad, the app or the event log shows which one it is. Fix the cause rather than getting used to the warning, because a system with an unresolved fault may fail to report the next real alarm.

Users should test the system about once a month: arm and disarm it, run a walk test so that every detector is seen to respond, confirm that SMS, calls and app notifications arrive, and sound the siren briefly after warning the neighbours. A professional service at least once a year (typically twice a year for commercial or high-risk sites) should also check the backup battery under load, the charging voltage, tamper switches, cable joints and mountings, detector lenses and coverage, the event log and the firmware version. Sealed lead-acid (SLA) backup batteries typically last 3 to 5 years, and less in hot places, because their life roughly halves for every 8 to 10 °C above 20 to 25 °C, so replace them on schedule rather than after a failure.

Yes, you still need an alarm, because the two do different jobs: the alarm detects an intrusion the moment it happens, sounds the siren and alerts people immediately, while cameras record and let you see what is happening. The simplest integration is wired: a PGM output of the panel connected to an alarm input of the recorder (NVR) or camera starts recording or sends a snapshot on alarm, and in the other direction the alarm output of an NVR or camera, for example from line-crossing detection, can be connected to a zone of the panel. The main benefit is video verification: before calling the police or going to the site, the owner looks at the images from that very moment. KDT's Smart Alarm Box (KB-SAB-IO64) can link camera events to its PGM outputs and sirens with its built-in if/then rule engine.

A PGM (programmable) output is an output that the panel switches on or off according to events you choose, such as arming, disarming, alarm, fire, a fault or a schedule. Typical uses are switching on the yard or building lights during an alarm, triggering a strobe or an extra siren, starting camera recording through an NVR alarm input, showing the arming state on an indicator light, or controlling a door lock or a smart-home relay. Transistor PGMs usually switch only small currents, typically tens to a few hundred milliamps, so drive larger loads through a relay and check the output rating in the datasheet. KDT's KB-M2 panel has 4 PGM outputs on board, expandable to 128 with expansion modules.

Yes. Many panels accept these detectors as 24-hour technical zones that work even when the system is disarmed and have their own siren pattern and notifications; KDT's Rhenium range, for example, includes a wireless smoke detector (KB-SD1-W, EN 14604), a carbon monoxide detector (KB-CMD1-W, EN 50291) and a water leak sensor (KB-WLS1-W, IP66 protection). This is a practical way to protect a home or a small shop, and being told remotely about smoke or a leak can prevent major damage. However, where regulations or the building's fire safety requirements call for a fire detection and alarm system to EN 54 or national codes, an intrusion panel with smoke detectors is not a substitute for it.

The KB-M2 is the hybrid control panel of KDT's Rhenium burglar alarm system: it manages up to 32 independent partitions and up to 192 wired zones (6 on board, expandable with up to 31 modules of 6 zones each), and supports up to 100 wireless devices over two-way FSK in the 868 MHz band with a range of up to 800 m in open space. It connects over Ethernet, Wi-Fi and a 4G (LTE) module; it reports events by SMS to up to 8 numbers with custom event filters, and is managed with a mobile app, unified cloud management and a local web interface. It has 4 PGM outputs on board, expandable to 128, and accepts up to 32 user codes. It is powered from the mains (220 V AC) or PoE, and an internal 12 V, 3000 mAh lithium-ion battery keeps it running during a power cut.

Yes. The alarm logic, sirens and outputs run on the KB-M2 panel itself, so detection and the siren do not depend on the internet or on any server, and the panel's web interface can be reached on the local network. The internet is only needed for access from outside the building with the mobile app and for receiving notifications; SMS goes through the 4G module over the mobile network and does not need the internet. To keep the panel reachable over the network during a power cut, put the modem, router and PoE switch on a UPS.

The simplest and most dependable method is a dry contact: a PGM output of the panel (or the relay output of a module) is wired to an input of the smart-home system to signal arming or an alarm, and in the other direction a relay or output of the smart-home system can be wired to a panel zone. A typical use is to switch off lights and close curtains when the system is armed in Away mode, and to turn on all the lights during an alarm. A network link, for example over HTTP or MQTT, is more flexible: KDT's KB-SAB-IO64 box has 6 inputs, 4 PGM outputs and HTTP and MQTT protocols and is compatible with the KB-WR1 wireless relay, which can switch loads of up to 10 A at 30 V DC or 7 A at 250 V AC. The key principle is that the alarm stays independent of the smart home, so it keeps doing its job if the central controller fails or the internet is down, and the smart-home system must not be able to disarm the alarm without authentication.

Usually yes: most wired detectors have a standard NC relay contact and run on about 12 V, so if they still work and the cables are sound, they can be connected to a new panel, but the zone wiring must be adapted to the new panel's scheme, including its end-of-line (EOL) resistor values and how the tamper is wired. Test each detector and each cable run before reconnecting it, and replace detectors that are old, have yellowed lenses or no longer suit the site's current risk. Old wired sirens can often be kept too, if their voltage and current suit the new panel's outputs. On KDT's KB-M2 hybrid panel, wired detectors connect to the on-board zones or to expansion modules, and wireless devices can be added wherever running new cable is difficult; KDT's KB-WM1-TR wireless transmitter can also connect a wired device to the wireless system.