Apollo 45681-277APO XP95/Discovery Addressable Sounder Base with Isolator, Loop‑Powered, White

Introduction to the Apollo 45681-277APO XP95 Addressable Sounder Base

The Apollo 45681-277APO XP95/Discovery Addressable Sounder Base with Isolator is a purpose-built, loop-powered sounder base designed for modern intelligent fire detection systems. Combining an integral short-circuit isolator, selectable tones and volume ranges, and compatibility with the XP95, Discovery and CoreProtocol families, this white polycarbonate unit is intended for indoor use where reliable audible warning and robust loop fault tolerance are required. The unit accepts an Apollo detector or beacon or may be used standalone with a blanking cap, making it flexible for a wide range of installation scenarios.

Key Features at a Glance

• Built-in short-circuit isolatorto maintain loop integrity and improve fault tolerance.
• Loop-poweredoperation — no external power supply required.
• Selectable tones and volumeswith two Apollo tones and two volume ranges (55–75 dB(A) and 75–91 dB(A) at 1 m).
• XP95/Discovery compatibilitywith XPert7 addressing for straightforward integration into Apollo addressable systems.
• Acoustic self-testfunction to verify sounder operation without visual inspection.
• Compact, white polycarbonate housing that fits a 4" isolated mounting base and meets design expectations for commercial and domestic environments.

Detailed Specifications and Benefits

The Apollo 45681-277APO is specified for reliable audible warning performance and resilient loop behaviour. Below is a breakdown of the key specification areas and how each benefits installers, system designers and end users.

• Manufacturer / Part no.: Apollo 45681-277APO — a recognised part from the Apollo XP95/Discovery family.
• Application: Designed for indoor use with XP95 / Discovery detector families (also supports CoreProtocol) — suitable for office, retail, residential and light industrial sites using intelligent addressable loops.
• Mounting: Fits a 4" isolated mounting base for easy retrofit or new installations, keeping wiring tidy and standardised.
• Material / Colour: White polycarbonate housing — durable, attractive and simple to maintain.

• Sound levels: Two selectable ranges — 55–75 dB(A) or 75–91 dB(A) measured at 1 m. This allows integrators to match sound pressure to the environment and regulations without changing hardware.
• Tones: Two selectable Apollo tones enable compatibility with local notification patterns and occupant expectations.
• Self-test: Acoustic self-test function provides a non-invasive way to verify the sounder is operational during commissioning and routine maintenance, reducing time on site.

• Power type: Loop-powered — the sounder draws power from the addressable loop, eliminating the need for separate power cabling and simplifying installation.
• Protocol signalling: Protocol voltage (peak-to-peak) operates between 5–9 V for communications — compatible with XP95, Discovery and CoreProtocol signalling levels.
• Quiescent / surge currents: Refer to the Apollo datasheet/installation guide for full electrical figures to ensure loop loading is correctly calculated during system design.

• Protocol: Fully compatible with XP95 and also supports Discovery and CoreProtocol systems, enabling integration into existing Apollo-based networks.
• Addressing: XPert7 addressing supported, making addressing straightforward during commissioning and ensuring accurate device management on intelligent fire loops.

• Standards: Designed to meet EN54-3 requirements for fire alarm sounders; consult the Apollo datasheet for full CPR/FG approvals and the latest CE/UKCA marking information.

Practical Benefits

• Reduced downtime and easier maintenance:The acoustic self-test saves time and helps confirm operation without manual activation or panel intervention.
• Improved loop resilience:The built-in short-circuit isolator helps keep unaffected devices online if a wiring fault occurs, limiting system impact and speeding up diagnosis.
• Simpler installs:Loop-powered operation, standard 4" mounting and XPert7 addressing lower installation complexity and materials cost.
• Flexible audible coverage:Selectable volumes and tones allow tailoring to spaces from small rooms to larger corridors while complying with local sound level requirements.

Use Cases and Scenarios Where the Apollo 45681-277APO Excels

This sounder base is well-suited for a wide range of installations, particularly those that already use Apollo addressable systems or where loop fault tolerance and easy maintenance are priorities.

• In office environments, the selectable volume settings let designers set warning levels appropriate for open-plan offices or meeting rooms without over-alarming occupants.
• The white polycarbonate housing blends with typical ceiling finishes and detector aesthetics, keeping the environment professional and unobtrusive.

• Retail stores and hotels benefit from the device’s audio options and compact footprint. The acoustic self-test helps facilities teams keep systems verified with minimal disruption to trading hours.

• For smaller addressable systems in apartments or small businesses, the loop-powered design reduces wiring complexity, and the isolator improves reliability where a single wiring fault could otherwise disable an entire loop.

• When upgrading conventional sounders to addressable systems, this product can accept a detector or be used standalone, making it flexible for staged upgrades without replacing the entire mounting or cabling infrastructure.

Comparisons with Similar Products on the Market

When evaluating alarm sounders and sounder bases, it is useful to compare the Apollo 45681-277APO against several categories of alternatives:

Some addressable sounder bases provide selectable tones and are loop-powered but lack an integrated short-circuit isolator. While typically less expensive up-front, these devices leave the loop vulnerable to a single wiring fault that can take down multiple devices. The Apollo model’s integral isolator provides a clear advantage in resilience and reduced downtime.

Conventional sounders and combined beacon/sounder units may offer comparable acoustic output, but they require separate wiring circuits and do not provide the addressability and diagnostics of XP95-compatible devices. For systems that require device-level monitoring, addressable sounder bases such as the Apollo unit are the better choice.

Other manufacturers offer loop-powered addressable sounders with varying feature sets. Key differentiators to consider are the presence of a short-circuit isolator, self-test functionality, supported protocols and ease of addressing/commissioning. The Apollo 45681-277APO stands out for combining XP95/Discovery compatibility, XPert7 addressing and an acoustic self-test in a compact, loop-powered package.

Customer Feedback and Testimonials

Official public testimonials specific to this part may vary by supplier. Typical feedback from installers and facilities teams for devices with this feature set often includes the following themes:

• "Ease of installation" — Installers commonly note that loop-powered devices that fit standard 4" bases reduce installation time and materials cost.
• "Improved resilience" — Maintenance teams often value the built-in isolator because it limits the impact of wiring faults and makes troubleshooting more straightforward.
• "Useful maintenance features" — The acoustic self-test is frequently cited as a practical maintenance aid that reduces the need for manual sounding tests.

While the above reflects typical industry sentiment for similar Apollo devices, specifiers should consult supplier reviews or request references for site-specific performance feedback.

Pricing and Value

The Apollo 45681-277APO offers a compelling balance of features and cost. With a suggested price of 41.95 (check local supplier listings for current pricing and availability), the unit provides integrated isolator protection, selectable audio settings and proven protocol compatibility — often resulting in lower total installed cost when compared to systems requiring separate isolators or additional wiring work.

Conclusion — Why Choose the Apollo 45681-277APO?

The Apollo 45681-277APO XP95/Discovery Addressable Sounder Base is a versatile, loop-powered solution for modern addressable fire alarm systems. Its key strengths are the built-in short-circuit isolator for improved loop resilience, selectable tones and volumes to suit a wide range of environments, XP95/Discovery compatibility with XPert7 addressing for simple commissioning, and a practical acoustic self-test for routine verification. These features make it an excellent choice for new installations, upgrades and replacement projects where reliability, ease of maintenance and straightforward integration are priorities.

For system designers and installers looking to balance performance, compliance and cost, the Apollo 45681-277APO represents a pragmatic choice that supports EN54-3 sounder standard requirements while delivering the flexibility and diagnostic benefits expected from modern addressable devices.