HES PA-300 Two-Tone Piezo Buzzer 3-28VDC
The HES PA-300 is a compact two-tone piezo buzzer designed for security and access control system signaling across a wide 3-28VDC input range. This device delivers dual-tone audible notifications for alarm events, door strikes, system alerts, and status confirmations with minimal power consumption. The piezo construction ensures reliable sound generation without external amplification, making it ideal for distributed alarm networks, control panel integration, and legacy or modern security installations where audio feedback is critical to operator response.
Key Features
- Two-Tone Audio Output: Programmable distinct alarm and notification signals. Operators can distinguish armed/disarmed confirmations from unauthorized access alerts without visual confirmation.
- Operating Voltage Range 3-28VDC: Accommodates legacy power supplies, modern 12VDC/24VDC systems, and low-power battery backup without regulation logic.
- Compact Piezo Form Factor: Minimal footprint for control panel mounting and distributed node placement. Eliminates external speaker infrastructure.
- Minimal Power Consumption: Piezo construction draws negligible current—suitable for battery-backed networks and low-power access control loops.
- Control Panel Integration: Direct wiring to relay outputs, door strike circuits, and alarm notification lines. No driver board required.
- Reliable Audible Signaling: Piezo resonance ensures consistent tone generation across temperature and supply voltage variance.
Deployment Architecture
The PA-300 bridges legacy and modern security deployments. In hybrid systems where older 9VDC door strike supplies coexist with modern 24VDC PoE-fed panels, the wide voltage tolerance eliminates the need for isolated power conditioning. The two-tone capability allows integrators to map distinct audio patterns to different event classes—zone-specific entry alerts, tamper signals, and system status changes—reducing false-alarm fatigue and accelerating operator response. On distributed campuses, the low power draw per node means alarm notification can reach every critical zone without upsizing the main control panel supply.
Installation is straightforward: one pair of leads connects to a relay output (normally open or latching), ground returns to the control panel reference, and supply voltage is applied. The device draws current only during the active tone duration—intermittent duty cycles on access events consume microwatts of standby power. No firmware configuration, no API calls, no network dependency. This simplicity is why the PA-300 remains common in retrofit projects and in new builds where budget or system constraints rule out networked alert infrastructure.
The piezo design also eliminates the maintenance overhead of electromagnetic buzzers—no moving coils, no relay chatter, no gap wear. A 10-year-old PA-300 sounds identical to a fresh unit. For facilities with centralized monitoring and long system lifecycles, this reliability translates directly to lower total cost of ownership and fewer unplanned maintenance trips to remote enclosures.
Integration Considerations
The PA-300 is ONVIF-agnostic and protocol-agnostic—it is an analog output device. Integration with modern VMS platforms (Genetec, Milestone, etc.) requires a bridge: the VMS triggers a relay or digital output on a control panel or relay module, which then energizes the PA-300 buzzer circuit. This extra step is negligible in wired security systems but becomes a consideration in wireless or IP-only deployments where every alert path must traverse software. For pure IP/ONVIF installations, evaluate networked alert speakers or tone generators instead. For hybrid or access-control-centric projects, the PA-300 remains the lowest-latency, most reliable audible notification option.
Marty AllisonPerspective based on aggregated IP Security Depot and affiliated engineering team experience.
We've installed the HES PA-300 in hundreds of access control panels, retrofit upgrades, and distributed alarm networks over the last decade. It's not glamorous—no IP, no analytics, no API—but it is genuinely bulletproof. The two-tone capability is what keeps it in our standard bill of materials: a short chirp for card-access grant, a sustained tone for unauthorized attempts, a rapid double-beep for system fault. Operators learn these patterns instantly and react faster than they would to a single monotone. On a 200-door university campus or a multi-building industrial facility, that audio differentiation is operationally worth the modest cost premium over a single-tone buzzer. The 3-28VDC range also solves a real field problem: legacy 9VDC door strike supplies coexist with modern 24VDC systems in most retrofit jobs. Rather than spec two buzzers or add a voltage converter, you spec one PA-300, and it works on anything. We've also found that the piezo construction is genuinely more reliable than electromagnetic buzzers in dusty or thermally extreme environments—no moving parts, no wear, no chatter noise that confuses operators.
Technical Highlights:
- 3-28VDC Operating Range: Eliminates the need for voltage regulation or separate power supplies in mixed legacy/modern installations. A single buzzer integrates into 9V, 12V, or 24V control systems without conversion logic.
- Two-Tone Piezo Design: Allows integrators to program distinct audio signatures for different event classes (entry grant, denial, tamper, fault) within the same control relay logic. Operator recognition is faster and error rates drop measurably on multi-alert facilities.
- Negligible Power Draw: Piezo construction consumes microamps at rest and tens of milliamps during tone. On battery-backed access control loops or solar-powered remote gates, the PA-300 has zero impact on power budget.
- No External Amplification Required: The piezo resonance is sufficient for indoor notifications and small outdoor coverage areas. Control panel integration is immediate—relay output to ground, no driver board or audio interface card.
- Proven Longevity: No moving coils, no relay contacts to wear, no electromagnetic chatter. Field units 15+ years old are indistinguishable from new stock in terms of tone consistency and reliability.
Deployment Considerations:
- Relay Drive Requirement: The PA-300 is not a line-voltage device. It must be driven by a 24VDC relay output, a solid-state output module, or a dedicated buzzer driver circuit on the control panel. Direct connection to a VMS network interface will not work—plan the control panel integration path before specifying.
- Outdoor Attenuation: Piezo buzzers are directional and lose efficiency in large open areas. For perimeter or parking-lot coverage, verify dB output meets site acceptance criteria. If outdoor range is critical, pair with an external horn speaker instead.
- Two-Tone Configuration: The PA-300 generates two tones as a product feature, but the actual alternation pattern (short burst, steady, rapid) depends on how the control panel relay is cycled. Confirm the panel firmware supports the desired alert sequences before installation.
- VMS Bridge Latency: If the buzzers are triggered via VMS software (e.g., Genetec platform event handler), there is a 100-500ms network delay between event detection and audio feedback. For immediate local response (access denial buzz), use the access control panel's internal relay, not VMS triggers.
- Acoustics and Annoyance: On a large panel with multiple buzzers firing simultaneously, the cumulative sound pressure can exceed 90dB in enclosed spaces. Test mock-ups in the actual installation environment to confirm operator acceptance and compliance with workplace noise regulations.
The HES PA-300 is the right choice for integrators and facilities managers building or upgrading access control networks where reliable, simple, low-power audible notification is non-negotiable—campuses, hospitals, industrial plants, and multi-tenant buildings with distributed door or gate control. For pure IP surveillance networks without legacy relay infrastructure, evaluate networked audio endpoints instead. Otherwise, you'll return to this buzzer again and again. Explore the full HES catalog for complementary power supplies, controllers, and signaling devices.
