We’re Tracking the Future of Security

Category: Intercom & Communication

  • Voice Evacuation Intelligibility Testing: From Audibility to STI

    Voice Evacuation Intelligibility Testing: From Audibility to STI

    A voice evacuation system can be loud enough to hear and still fail to deliver an understandable instruction. Audibility confirms that a signal rises above the environment; intelligibility asks whether listeners can correctly understand the words. Commissioning must address both outcomes.

    This distinction is especially important in transport halls, factories, atria, tunnels and other spaces with reverberation or changing background noise. Related fire-safety guides are available in Articles & Analysis and the Fire Safety archive.

    Begin with the design objective

    Identify the occupied zones, expected ambient conditions, message languages and emergency actions. Review speaker layout, amplifier loading, zoning, survivability and message priority. Acceptance criteria must come from the adopted codes, approved design documents, listed equipment and the authority having jurisdiction; one score should not be presented as universal.

    Separate level from clarity

    Measure the emergency message against representative background noise, but do not stop after confirming sound pressure. Excessive level can worsen reflections or distortion. Inspect speaker aiming and spacing, competing announcements, reverberant finishes and obstructions. A quiet test after hours may not represent an occupied building.

    Use STI or STIPA carefully

    Speech Transmission Index methods, including STIPA, estimate how the transmission path preserves modulations important to speech. The test signal, meter settings, measurement positions and background-noise conditions must follow the selected method and project procedure. Record the measured value with its location and operating condition rather than reporting an unexplained site average.

    Plan representative measurement points

    • Include zone boundaries, corners, areas below balconies and locations between speakers.
    • Test near machinery, ventilation outlets and other recurring noise sources.
    • Verify each message path, emergency microphone and automatic message sequence.
    • Check fault monitoring and backup-power operation separately from acoustic performance.

    Diagnose a failed area systematically

    A poor result may come from reverberation, low signal-to-noise ratio, overlapping speaker arrivals, distortion, incorrect equalization or an unsuitable speaker pattern. Corrective action might involve changing aiming, spacing, level balance, delay, acoustic treatment or the message itself. Short, direct wording often performs better than a complex sentence, but message changes require approval.

    Document and retest

    Record the instrument, calibration, test signal, floor plan position, ambient condition, system mode, measured level and intelligibility result. Link every defect to corrective work and repeat the same measurement after changes. Periodic tests should use a controlled baseline so that a genuine deterioration is distinguishable from a different test setup.

    Sources

  • Two-Way Radio and Communication Systems for Security Teams

    Two-Way Radio and Communication Systems for Security Teams

    When a security operations center needs to reach every guard on a property at once, or a guard needs to call for help without dialing a number and waiting for someone to answer, two-way radio still outperforms cellular communication — which is why it remains standard equipment for security teams even in facilities otherwise saturated with smartphones and networked devices. The technology has changed substantially from the analog handhelds of a generation ago, but the core advantage, instant one-to-many communication independent of a carrier network, has not.

    Analog vs. Digital Radio

    Analog radios remain in use for their simplicity and low cost, but digital radio systems, built on standards like P25 (common in North American public safety) or DMR (widely used commercially), offer clearer audio at the edge of range, encryption options, and the ability to carry data alongside voice, such as GPS location or status updates. Digital systems also support trunking, where a pool of radio channels is shared dynamically across many users and talkgroups rather than each group being locked to a single dedicated frequency.

    Talkgroups and Channel Discipline

    Larger security operations organize radio traffic into talkgroups, separate channels for different teams, shifts, or functions, such as patrol, dispatch, and emergency, so that routine chatter does not bury a genuine emergency call. Effective radio discipline (clear callsigns, brief transmissions, a defined process for emergency traffic to interrupt routine use) matters as much as the hardware, since a radio system is only as useful as the protocol governing how people use it under stress.

    Coverage: DAS and Repeaters

    Radio range is limited by building materials, terrain, and radio-frequency interference, which is why large or below-grade facilities often deploy a distributed antenna system (DAS) or repeaters to extend coverage into stairwells, parking structures, and basement levels where a direct radio signal would not reach. Many jurisdictions now require in-building radio coverage systems for first-responder communication as a life-safety code requirement, separate from and in addition to whatever radio system a security team uses day to day.

    Integration With Duress and Dispatch Systems

    Modern radio systems increasingly integrate with software dispatch platforms, letting a control room see which radio units are active, log call history automatically, and trigger a radio-based duress alert that surfaces on a dispatcher’s screen with the reporting unit’s identity and location rather than requiring a verbal report during an active incident. This integration turns the radio network from a simple voice channel into a data source that feeds incident logging and after-action review.

    Interoperability With Public Safety

    Facilities that regularly coordinate with police or fire, such as stadiums, hospitals, and large campuses, often need their radio systems to interoperate with public-safety agencies during a major incident, which typically means supporting shared frequencies, mutual-aid talkgroups, or gateway devices that bridge a private security radio system with a public-safety network without requiring every private-security radio to be reprogrammed on the spot.

    Reference sources

  • Video Intercom and Communication Systems: The Missing Link in Modern Access Control

    Video Intercom and Communication Systems: The Missing Link in Modern Access Control

    Video intercom systems sit at the point where access control, video surveillance, and building communication converge. A visitor at a door is simultaneously a video subject, an access-control event, and a two-way audio interaction — and modern IP-based intercoms are designed to treat all three as a single, integrated workflow rather than three separate systems bolted together.

    From Analog Buzzers to Networked Endpoints

    Legacy intercoms were closed, point-to-point systems: a door station wired directly to a handset inside. IP video intercoms instead operate as network endpoints, capable of streaming video to a central VMS, triggering access-control credentials, and routing calls to a receptionist, a mobile app, or a remote guard station depending on time of day or staffing. This shift means an intercom call can be answered from anywhere with network access, not just a fixed panel next to the door it serves.

    Integration With Access Control and Visitor Management

    The strongest deployments tie intercom systems directly into access-control platforms so a single interaction — a visitor pressing a call button — can trigger identity verification, log an event, and grant a temporary credential without separate manual steps. Some platforms extend this further into visitor-management systems, allowing a pre-registered guest to be recognized at the door and granted access automatically, with the intercom serving as a fallback for unregistered visitors.

    Where Video Intercoms Add the Most Value

    Multi-tenant residential buildings, corporate lobbies, loading docks, and remote or unstaffed facility entrances see the clearest return: each is a location where someone needs to grant access without being physically present. Cloud-managed intercom platforms let a single remote operator cover multiple sites, reducing the staffing burden of traditional front-desk security while preserving a human decision point at every entry.

    Deployment Considerations

    Bandwidth and power planning matter more for video intercoms than for traditional access readers, since each unit is effectively a camera, microphone, speaker, and access-control endpoint drawing continuous power over Ethernet. Organizations should also plan for redundancy: because intercoms are often the only way a legitimate visitor can request entry, a network outage that takes the intercom offline can inadvertently block access as effectively as a security incident.

  • Mass Notification Systems: Emergency Communication for Complex Sites

    Mass Notification Systems: Emergency Communication for Complex Sites

    Emergency communication is no longer limited to bells, sirens or a single public-address message. Modern mass-notification systems are designed to deliver clear, coordinated instructions across multiple channels and to reach people wherever they are.

    Why communication fails during emergencies In a crisis, occupants may not know what has happened, where the hazard is or whether they should evacuate, shelter in place or avoid a specific route. A simple alarm tone communicates urgency but not context. Voice messages, visual displays, mobile alerts and desktop notifications can provide more actionable information.

    Multiple channels, one message A modern platform may integrate voice alarm, public address, SMS, mobile applications, email, digital signage, desktop pop-ups and radio interfaces. The goal is not to send as many messages as possible; it is to ensure that the same verified instruction reaches the right audience quickly.

    Integration with detection systems Emergency communication becomes more powerful when linked with fire alarms, gas detection, security systems, weather alerts and building management platforms. A confirmed incident can trigger pre-approved message templates while operators retain control over escalation.

    Message intelligibility A loud announcement is not necessarily an understandable announcement. Reverberation, machinery noise, language differences and hearing impairment can all reduce comprehension. Acoustic design, speaker placement and message testing are therefore essential.

    Cybersecurity and resilience Because many notification platforms use IP networks and cloud services, they require strong authentication, role-based permissions and fallback communication paths. Emergency communication must continue even when part of the IT infrastructure is unavailable.

    The best systems combine automation with human judgment. Predefined workflows reduce delay, while trained operators validate the situation and adapt instructions as conditions change. The real performance measure is not how many channels a platform supports, but whether people receive a clear, trusted instruction when seconds matter.