Overview about the Alarm Systems

On this page you will find general insights and answers on Silentron alarm systems. In shortages must contact your installer and / or carefully read the supplied manual of each equipment. If necessary, write to silentron@silentron.it, accurately placing the question: Silentron directly responds in the shortest time possible.

  • Systems


    All control panels that are connected to the mains power supply are equipped with power supply unit and backup batteries. They supply power to detectors, self-powered sirens and phone dialers in addition to maintaining backup battery charge. You must place the outmost care in properly sizing a system’s power supply requirements in order to avoid problems over time.

    Power supply: operating voltage and power supply capacity are stated by the manufacturer on the device’s label.
    The power supply unit of equipment operating at a 12V nominal voltage rating with backup battery, must deliver about 14.5V voltage in order to properly charge of the battery. Delivered current must be enough to power the entire system with 230V AC mains voltage. In order to calculate the average power supply requirement of the system during normal operating conditions you must therefore add together the power used by batteries and by the other installed equipment, including central the control panel. This amount must be equal or less than the power delivered by the power supply unit and is cautiously calculated at 80% of the nominal voltage rating.

    Battery: 12V voltage rechargeable sealed lead batteries with current declared by the manufacturer are mostly used for alarm systems. As greater power entails larger sizing, choice is linked to the room that is available in the control panel.
    A backup battery is always required, as it ensures system’s operation in the event of power loss and as it provides the system with the additional power that is required in the event of an alarm.
    The quality of the battery is very important for the efficiency and integrity of the system. Rechargeable batteries have an average life of about 4-5 years and should, therefore, be checked and replaced after this period even if they seem undamaged.
    Battery power requirements change according to its charge level. Current regulations required that a battery should be charged at least 10% of its nominal voltage rating. Silentron always advises which type of battery must be used The control panel’s instruction manual also supplies a table to guide you in calculating backup power requirement and resulting battery capacity based on installed accessories when different type of batteries can be used.

    Power supply issues: a mistaken power sizing, under-voltage or power failure, always causes problems. An incorrect power supply means that any small disturbance on the power grid will reflect on the electronic equipment, causing random and unfathomable faults. A flat battery or a faulty power supply unit can lead to false alarms or the inability to silence the alarm system, difficulty in arming/disarming it and other unpleasant issues.

    Caution ! On any alarm system, faults that are not linked the actual malfunctioning of an equipment are almost always caused by power issues!

    Calculating average power supply usage: let’s use an example to better understand how to correctly calculate the size of a typical “ready to use” hardwired system for residential applications.

    Example 1: control panel with 14V 1 power supply unit (data stated on product plate) - cautiously calculated at 80% of the voltage rating = 800mA
    a) control panel power usage 80mA + keyboard usage (20mA) + 12V 2.2Ah battery (10% = 220mA)
    b) detectors power usage: 4 infrared devices (60mA) + 1 dual technology (30mA) + 5 magnetic contacts (0 mA)
    c) self-powered siren with built-in battery power usage: board (5mA) + 12V 2.2Ah battery (10% = 220mA)
    d) loss of current due to cable resistance can be disregarded when conductors are of a suitable diameter (at least 0.50mm diameter/not longer than 50m), but can become influential when smaller diameters and longer cable lengths are used.
    Case 1) System Power Use: 635mA = correct sizing
    Case 2) System’s power usage with 12 dual technology detectors specified in item b): 905mA = critical sizing
    Case 3) System’s power usage with 12V 6.5Ah control panel battery: 1060mA = incorrect sizing

    Calculating backup power requirement upon loss of primary 230v power: in the event of power failure the above described system operates only thanks to the control unit’s battery. Siren’s battery powers only the siren and never powers the system. we have:

    Case 1) power available cautiously calculated at 80% of the nominal voltage rating (EN standards): 1760mA
    System’s power usage: 635mA
    Backup power requirement in hours: 2h 46m = inadequate as system’s design does not comply with EN 50131.1 standard which requires at least 12 hours of battery life without main power supply for 1 and 2 security levels and 60 hours for 3-4 levels.
    Case 2) backup power requirement in hours: < 2h = inadequate
    Case 3) power available cautiously calculated at 80% of the nominal voltage rating (EN standards): 5200mA
    System’s power usage: 635mA
    Backup power requirement in hours: around 8h which are still not enough in terms of time and power supply unit’s sizing is incorrect.

    Conclusions: Continuing to use our example for a wireless control panel the total power usage of a wireless control panel drops to 140mA and even though 4 hardwired infrared detectors are installed. In this case therefore the power supply unit is abundantly adequate and backup power requirement in hours exceeds the 12h required by the standard.
    Along with other facets, this is an important element that should be taken into account when selecting between hardwired or wireless solutions.


    Wireless systems Hardwired systems Notes
    2.1) Cost of equipment greater lesser ensure adequate power supply unit and battery
    2.2) Installation cost lesser much greater costs vary greatly based on installer
    2.3) Installation flexibility much greater linked to the structure installer's skill is very important
    2.4) Maintenance battery inspections General inspections verify wireless devices backup power
    2.5) Security good good check radio transmissions control

    In general, there are greater benefits in using wireless alarm systems for finished and furnished rooms that are approximately up to 400 square meters. Thanks to the flexibility in which devices may be appropriately placed, the same also holds for outdoor installations located near the premises.
    Wireless alarm systems’ main limit concerns the radio range of the devices (see relevant paragraph).
    Traditional systems involving cable laying are more suitable to large commercial/industrial environments and/or for buildings under construction or being restructured.

    Maintenance: alarm systems maintenance mostly consists in checking proper power supply and rechargeable batteries’ efficiency. Checking each devices’ proper operation can be managed directly by the user at any time.
    For wireless systems it consists in replacing batteries when it is reported by the equipment or periodically (every two to four years, depending on device and brand).

    Safety: as far as the security being offered is concerned, the two level 1, 2 and 3 installation solutions that comply with EN 50131 standard are similar. Both kind of systems offer 24/7 tamper protection although in a different way from a technical standpoint. Attempts to tamper hardwired or wireless systems require very different approaches, but recent control panels are able to report them quickly, provided that the installation is carried out in a workmanlike manner.

    A3. Wireless systems - wireless radio transmissions arrow_drop_up

    The different wireless devices communicate with each other via radio (one-way or two-way radio according to requirements and characteristics) like any GSM mobile phone. Operating frequencies and range are regulated by specific laws. The devices used in the industry are SRD category (short range) devices and generally offer enough capacity for small to medium installations ranging from an office to a large villa.
    All physical obstacles clearly reduce these devices’ range especially if same are metal ones. This is why we recommend to check range on site before prior to installation. Silentron control panels are supplied with tools that check radio signal quality and range to allow to quickly check same. Special signal repeaters may be used as required in order to ensure radio coverage while preserving regulatory radio transmission limits.

    Wireless systems operating on different channels, or better operating over different frequencies, obviously offer a greater security and , steering clear of continuing radio interference reports and thus ensuring less trouble and greater reliability to the user. All Silentron units have been operating over at least two frequencies (according to regulations) for many years. The latest two-way models operate over two channels for each of the two frequencies being used thereby supplying the greatest transmission reliability.

    Using radio systems that claim to reach distances in kilometers are definitely not recommended. They may seem batter, but they actually create problems as they use more power and because they inevitably interfere with other similar devices within their range being more easily detectable over greater distances which increases the risk of tampering thought advanced means. Attaining an adequate radio range that meets local requirements is always the best solution for a wireless alarm system’ smooth operation over time.

    A4. Wireless systems – RANGE OF REMOTE CONTROLS arrow_drop_up

    Arming and disarming an alarm system using remote controls is always one of the most practical solutions, but in addition to range considerations (background noise, physical obstacles’ interference) we must also take into account that the remote control is a handheld device that is used in different places and positions. It follows that great, yet absolutely normal, range changes may inevitably occur due to irradiation plane variations (horizontal or vertical position of the remote control) and induced reflections (the remote position with respect to the surrounding space). It is a good idea to get used to managing the control panel from the same position and to hold the remote control in the manner in which it best operates.

    Radio range should not be greater than the required limits as remote controls can be "copied" by reading their code with special detection equipment. This may seem as a limit and may even result in faulty operations when used in specific positions, but it actually diminishes the likelihood of the remote being copied as well as random operations which may occur when a key is inadvertently pushed. Copying the code of Silentron systems’ remote controls does not produce any result as copied code is never reused (rolling code), but the widespread accidental use of the remote control (remote control in your pocket, purse) at reduced ranges greatly limits the likelihood arming/disarming the system without wanting to.

    A5. Wireless systems - IRREGULAR BATTERY CHARGEarrow_drop_up

    Batteries are vital for wireless systems. Silentron’s control panels always report any impending battery depletion. Many detectors also report it locally through LED indicators or buzzers. Battery life is linked to devices’ operation. For example: if a magnetic contact protects a door that is opened 100 times each day, the battery will drain much faster than the one of a door being opened once a day. Likewise the battery will drain earlier when a siren sounds every day because the user forgot to turn off the alarm and so on.
    Battery life that is stated in manuals is therefore always based taking into account a "normal" use of the equipment which can considerably vary.

    Should batteries drain quickly, in a matter of months rather than years or at any rate in a much shorter time than the one stated in the manual, you must use a meter to measure device’s power use requirement and ensure that it is a microamperes (uA) amount and never milliamperes (mA) before you replace the battery.
    The device must be replaced if you measure 1 or more milliamperes power being used as the battery will otherwise drain again in a short time. Battery devices are designed and built with selected and more expensive components in order to require very low power absorption and therefore many years of usage. Despite this, the loss factor of some components (capacitors) may increase as they age thereby causing an abnormal amount of power being used which drains the battery even when they operate properly.

    A6. DETECTORS SELECTIONarrow_drop_up

    Intrusion and/or break-in detection is clearly the primary purpose of an alarm system. Selecting the appropriate type of detector or sensor and its positioning is crucial to achieve this purpose. Right now we are going to focus only on the most commonly available devices used to protect indoor areas, window frames and promises perimeter outdoor areas, setting aside detection systems for larger outdoor areas. Since the primary goal of an alarm system is to deter, in other words to begin with detecting the intruder before implementing alarm devices and distress calls. Detector selection must take into account:
    - required type of protection (theft: protection of property without people on premises – preventing aggression: protection of property and people)
    - indoor and outdoor characteristics of the premises and of its nearby areas.

    We can divide detectors into the following main categories:

    1. volumetric motion detectors: that protect an area, signalling when targets are moving within this area by detecting and analysing physical phenomena that are linked with human movements. This means that these devices do not actually recognize an intruder, distinguishing an intruder or an animal from any other moving mass, but rather detect the specific typical features of a human being.

      The most common volumetric motion detectors are:
      Infrared Detectors, generally called P.I.R. (passive infra red), that warn about a human movement in the premises, by detecting the target’s different temperature compared to the background. These device’s use an optical element (Fresnel lens or reflecting mirror) and may cover vast areas based on their specs. The most common PIR detectors cover an area from about 100° to 12m in length and have the most sensitive areas at different heights. Corner installation is the ideal positioning of these detectors.

      Volumetric microwave detectors which employ a microwave Doppler effect consisting in the distortion of the electromagnetic signal that is radiated in the air when it is crossed by a solid body. The reflected signal can be analyzed since its frequency varies.

      Dual technology detectors which are formed by a P.I.R. detector and a Doppler effect microwave detector which normally triggering an alarm only when a target is detected by both devices (AND setup). This setup is used to decrease the number of potential false alarms rather than to increase security which would at any rate be assured by the infrared detector (the minor technology). Potential false alarms are decreased by monitoring two different physical phenomena and signalling an alarm only when detection occurs at the same time.
    2. Shock detectors which protect surfaces, such as walls or windows, by analyzing the vibrations induced by break-in attempts aiming to distinguish them from random caused vibrations. This is not a simple task because these phenomena are very similar. Significantly different devices in terms of quality and employed technology are available on the market as they caters to different industries. This is why we electromechanical devices (inertia sensors) and electronic ones (selective microphones - high security) which are installed on the surface to be protected. A shock sensor can be integrated into other detectors for residential/business applications.
    3. “Spot” detectors protect a specific spot which is usually an access and signals its opening. The most common ones are magnetic contacts which are installed to protect windows/doors of any kind with more or less sophisticated detectors.
    4. Barrier Detectors protect gaps, reporting transit through the "barrier" normally invisible generated from the device on the basis of the technology used. There are two main types of barriers: passive detector barriers, or curtain barriers, which employ P.I.R. volumetric motion detectors and a suitable lens that create the barrier and alert that the access point has been crossed; active infrared detectors, which use a set of "photocells" overlaid in such a manner as to create several beams between the transmitter section and the receiver with the alarm being triggered when beams are crossed.

    All of these detectors are available in the traditional hardwired version, connected by cable, and "wireless" version, i.e. with radio transmitters. Wireless detectors are clearly more expensive, especially when high quality transceiver section are being used, but their cost is compensation by lower installation costs. There are no appreciable differences between the two types as far as safety is concerned.

    Achieving protection Where possible, the best protection is achieved by controlling nearby outdoor areas using volumetric motion detectors or barriers and the premises’ perimeter, or at least all of its access points, through barrier, shock or “spot” detectors. Indoor areas can be protected only when people are not located within the premises. Employing all of these three types of protection is not always possible. Should this be the case, priority should be given to perimeter protection as it may be used with or without people being in the premises. Indoor and outdoor protection can be limited to transit routes.

    In order to achieve a good level of protection you must therefore use the type of detectors which are most suitable to the rooms being protected in terms of what you want to achieve when using the alarm system.

    A7. ALARM DEVICES SELECTIONarrow_drop_up

    Please remember that the main purpose of an alarm system is to deter! Everything that happens once an intruder is detected could get the intruder to stop or to continue his criminal action. Getting an intruder to give up is the best result that you achieve from an alarm system. This is why the selected alarm devices must be highly effective for this purpose.

    Outdoor sirens are a vital tool as they combine the deterring element with a rescue/prompt action request. Siren operates locally and broadcast their sound over several hundred meters. Sirens alert intrusion but also disturb neighbours, who are not always interested or in favour of an action request. The noise produced by a false alarm only achieves having disturbed people. A siren can also be easily silenced when it is not properly installed (if it is easily accessible). Antifoam devices or other similar protections are useless, since an outdoor siren can be silenced or even torn and immersed in water when it can be reached.
    It follows that:
    a system equipped with an outdoor siren must be immune to false alarms
    an outdoor siren must be totally unattainable or otherwise difficult to reach
    two outdoor sirens are better than one

    Indoor sirens. the psychological effect of an outdoor siren is strongly diminished when an intruder is able to access the premises as its sound is much less noticeable. Any system must therefore have an appropriate number of indoor sirens which prevent listening to what is happening around and should confuse anyone located in the premises thereby creating a reason to stop the criminal endeavour.

    Solutions with speakers sirens for both outdoor and indoor protection. Using sirens which broadcast recorded deterring messages before high-power sounds allows to greatly diminish any neighbourhood disturbance and, also, to avoid frightening anyone located within the premises while preserving a certain effect on the intruder, who immediately understands that he has lost the element of surprise.
    Avoiding to disturb neighbours is definitely a useful way to get cooperation in the event of false alarms (which can happen more often when using outdoor detectors).

    Reactive Solutions. Each alarm system can be equipped with devices that react to the intrusion creating a situation that makes it impossible for the intruder to continue with his actions. Generators that produce fog (those used for music concerts) or irritant spray (cans against aggression that are finally legal in Italy) are undoubtedly effective. These devices features several management and controlling systems that prevent them from being triggered by mistake and are the most modern type of defence and reaction to a malicious intrusion event. They must be properly installed and be setup in such a way as to not cause issues during normal conditions. For this reason you must use a professional installer when installing this kind of equipment. These devices offer the following different characteristics:
    - Fog can be used for residential, sales or industrial applications and in any room according to the generator’s size. The fog that is produces and that saturates the environment, is not toxic and is dispersed over time. Resetting the device after an alarm has been triggered is somewhat expensive, but its cost is acceptable in view of its results.
    - Irritating spray generator diffuse chilli powder with its well known and temporary effect on mucous membranes. They should not be used in very large areas, because their objective is to get in the way of the aggressor rather than saturating an environment. Their use is recommended to protect shop windows against breakage, areas with safes, cabinets and similar rooms, hallways or special access areas. The cost to reset these devices after activating is low, but it may increase when used in large spaces (installation error!).

    Other deterring elements. Any other means that distracts or disturbs an intruder can be useful in the event of an alarm since an alarm system mostly produces psychological effects on a trespasser. Although simply turning the lights on has a minor effect that is not always useful as disconnecting the power is a simple task, we recommend using such means along with turning on water sprinklers or opening an enclosure where animals are located. Current professional control panels can enable all kinds of home automations triggered by an alarm or on demand. These opportunities should be properly exploited to achieve the most effective system available.


    The control panel is the heart of the system. It monitors and manages all of its operations. A good control panel is easy and intuitive to operate and should facilitate management and operations. Most people will stop using an alarm system if its control panel is too complex and difficult to operate.

    Choosing the right product is not easy for a layman, but we can suggest the following elements for your evaluation.
    Hardwired or wireless control panels. Unless there are specific obstacles, the best solution is a control panel that offers both options. See items A2 and A3 for additional information.
    Batteries. As control panels operate 24/7 even during a power failure, employed batteries must properly take into account the size of the system in order to avoid the lack thereof even during a short power failure (see A1). Caution! Although rechargeable, the batteries of a control panel are not everlasting and can provoke faults which usually lead to false alarms when they are very worn-out.
    Equipment used to communicate with the outside world. Almost all current control panels are supplied with built-in communication devices which are vital for the security of the system. These devices may operate over the landline, GSM, radio or the web. This last option allows you to easily and quickly manage the control panel remotely using an APP. Caution! While telephone devices operate also during power failures, WEB ones (home router) usually do not. The router must therefore be equipped with batteries when the control panel uses communication devices operating over the web!
    External communication: it is always better that you are directly and immediately warned by the control panel in the event of an alarm. Entrusting your assets to third parties may offer greater safety, but you will always be more concerned about your own assets compared to anyone else and will therefore supply greater care and prompter actions in the event of an alarm. When a call for private or public assistance is made, the outcome is quite different if a person rather than a machine is making the call. In any event, current control panel allow you to setup many types of alerts thereby reaching many phone numbers in addition to surveillance centres.
    Controlling devices. Fixed keyboards, remote controls and ultimately a Smartphone APP allow you to fully use the system. Each solution offers different advantages and disadvantages. Apps solve most issues, but we recommend that you do not make your Smartphone accessible to anyone in order not to make available to anyone the best means to arm and disarm the system.

    Installing the control panel. We used to try to hide the control panel as much as possible so that it would not be found. This led to testing and maintenance accessing issues. Today’s alarm response times and alerts make trying to damage the control panel to sabotage the system unnecessary. You must of course still keep it in a safe place to ensure that at least one alarm is triggered before it is discovered and damaged. A siren should not be installed in the control panel as it would allow it to be quickly identified.


    These devices are now very "fashionable" and are also very helpful in public places and/or sales and industrial companies. A camera is basically irrelevant as a theft or aggression deterrent, especially in a residence, as the attacker can simply wear a pair of tights to become unrecognizable. Our work does not concern using video to search for the perpetrator of a crime. As previously mentioned, our objective is to use the alarm system to avoid the event altogether, not to film it.
    Nevertheless, photographs of real-time events can still be useful, if only to reassure you in the event of a false alarm. Several products that transmit video frames together with alarm alerts or when requested remotely by the evaluation elements customer are available on the market with this objective in mind. This type of “video confirmation” is almost always asked for when the system is connected with a private surveillance centre in order to avoid unnecessary action to be taken.

    B1. FALSE ALARMarrow_drop_up

    The so-called "false alarm" is a burglar system’s most common flaw. We must distinguish false alarms from improper alarms.

    a) False alarm: responsible party
    a1) event caused by a flawed component of the system manufacturer
    a2) flawed connections and/or high interference on connections (hardwired systems) installer
    b) Improper alarm:
    b1) random event caused by local phenomena to which detectors are sensitive installer
    b2) incorrect positioning of one or more detectors and/or incorrect setting installer
    b3) event caused by user's carelessness user

    In order to accurately and successfully intervene, the source of the event must be understood and diagnose in both cases. The inability to understand what has happened often leads to unnecessary product replacements, with money and time being used to no end.

    False alarm: as no flaw gets repaired on its own and the fault with continue to occur or the unit will stop working when a device is faulty. The device must be replaced once fault has been ascertained. Warning: It is highly unlikely that a device is faulty as Silentron systems’ quality is definitely very high. You must rule out all other possible reason for the event before replacing a device as returning a unit that is not faulty nevertheless involves costs.

    Improper alarm: a detector triggers an alarm for various reasons, not only in the event of an intrusion. The installer must know how each installed device operates and consequently seek to identify for which reason the event has occurred. This is a complex matter and diagnosing the issue is the most difficult phase which demonstrates an installer’s expertise.
    Silentron equipment’s instruction manuals state each devices operating conditions. Silentron can also suggest specific operating solutions when assistance is required by working with the installer who can and should provide precise data about local condition and device positioning as he is located on site.
    All Silentron’s systems are equipped with several useful functions to minimize improper alarms (sensor calibration, double confirmation, two detectors and/or area setup with AND function, temperature compensation, etc.), but appropriate operations (appropriate device in the appropriate position) and positioning (installed in the most suitable place and position) are crucial for smooth operations.
    In addition to the above, also those who use the alarm system must know how it operates and avoid adopting a routine or behavior which conflicts with its smooth operation. The installer must be advised before installation if you always leave windows open, if you have pets, if a protected area can be accessed from different approaches allowing him to suggest suitable devices.

    General rule: a greater degree of "security" (redundant detectors, excessive adjustments, outdoor and/or difficult environment protection) inevitably leads to an increased improper alarm risk.
    The best installation solutions involve a reasonable compromise between required intrusions reporting operations and those elements that user finds essential.

    Outdoor protection: Silentron offers several intrusion reporting solutions which begin outdoor near accesses. In this case one must take into account also animals (especially birds and large insects), weather condition factors (major storms, powerful wind) and any other facet that may have an effect on detectors. Improper alarm risk is dramatically reduced outdoors when . two detectors of the same protected area are setup with the AND function.

    B2. ALARM FAILUREarrow_drop_up

    This is a critical event as it undermines protection. Silentron systems offer users the capability to check alarm system’s proper operations on a daily basis (it should be performed at once a month). Not taking into account faults to one of the system’s devices, alarm failure is more likely to occur in wireless systems. It is usually caused by radio interference and our control panels are equipped with controls checking radio frequency operation that can be enabled to report condition before an alarm fault occurs.
    Alarm failure can also be caused by a detector’s excessively low sensitivity. Adjust settings and/or activate temperature compensation function when this happens during the summer and the premised get overheated.

    Siren alarm failure: an alarm panel could be “alarmed” without enabling its siren. Check the alarm event log which would display it and repair faulty siren (check for depleted rechargeable batteries or dead batteries).

    B3. TELEPHONE CALL FAILUREarrow_drop_up

    Silentron control panels are equipped with built-in telephone transmitters connected over fixed lines, GSM or both (best solution). Check dial tone (PSTN) or the radio signal (GSM) in the event of alarm transmission failure. Also check setup to verify that each alarm event has been properly linked with the various users (phone numbers) that should be called. Check provider’s telephone service continuity. Users can perform alarm telephone transmission tests at any time.

    B4. UNSTABLE WEB CONNECTIONarrow_drop_up

    The latest generation of Silentron control panels are supplied with APPs that allow you to manage them online. Take your time to carefully setup and test everything. Before looking for device flaws, we recommend checking connectivity appropriateness as an ensuing anomaly could be due to the router used by the provider’s network service or by network being congested, etc.
    For these reasons Silentron always recommends installing an additional telephone communication device to connect to the web.