Hochiki CHQ‑DZM(SCI) Dual‑Zone Detector Monitor Interface, 2 Zones, 17–41 V DC

Introduction to the product and its key features

Hochiki CHQ‑DZM(SCI)is a purpose‑built dual‑zone conventional detector monitor/interface for Hochiki ESP analogue addressable loops. Designed for professional fire‑alarm installers and system integrators, this module converts two independent conventional detector circuits into a single ESP address on the loop. It provides full short/open monitoring for each zone and includes an integral short‑circuit isolator (SCI), making it a compact, resilient solution where multiple conventional circuits must be reported to an addressable control panel.

• Two independent conventional zones— monitors two separate conventional detector loops and reports them via one ESP address.
• High detector capacity— supports up to 60 conventional devices in total (typically 30 per zone for the standard variant).
• Open/short monitoring and SCI— full fault reporting and isolation reduce nuisance impacts of wiring faults.
• Hochiki ESP protocol— DIL switch addressing, protocol self‑test and integrity checking ensure reliable operation on modern addressable loops.
• Flexible mounting— available as a module, DIN‑rail/boxed variant and specialist IS/HFP/marine/railway versions for regulated environments.

Detailed description of specifications and benefits

The CHQ‑DZM(SCI) operates from a nominal addressable loop voltage in the range of17–41 V DC. It requires an auxiliary 24 V DC supply for powering the monitored conventional detectors and the module electronics. In low‑power standby conditions the device draws typically around110 µA, with quiescent and alarm currents stated in the official datasheet — installers should consult the datasheet for exact figures to size power supplies and batteries correctly.

Each of the two conventional zones can support a substantial number of detectors — up to60 devices in totalon the standard electrical limits (commonly 30 per zone). The module provides comprehensiveshort/open‑circuit monitoringand reports faults back to the panel. The built‑inshort‑circuit isolator (SCI)protects the rest of the loop from downstream short faults, improving system resilience and reducing the likelihood of a complete loop failure due to wiring damage.

Addressing is straightforward using the DIL switch, assigning asingle ESP addressto the dual‑zone interface. The unit uses theHochiki ESPprotocol, which includes self‑test and integrity checking routines to ensure the module and connected devices remain healthy. The interface reports open/short faults as well as alarm conditions from either conventional zone, enabling the control panel to present accurate zone/status information to users and engineers.

Typical operating temperature ranges are around−10 °C to +50 °Cwith storage limits of approximately−30 °C to +60 °C. Several variants are offered to suit regulated or hostile environments: a DIN‑rail/boxed version for tidy installation, intrinsically safe (IS) versions for hazardous areas, and HFP/marine/railway variants where specific approvals and electrical limits are required. Because electrical limits and certified detector counts vary by variant, always confirm the exact SKU and consult the manufacturer datasheet before specifying or installing.

• Reduces address usage on the ESP loop by consolidating two conventional circuits into one address.
• Enhances reliability with open/short monitoring and short‑circuit isolation.
• Simplifies retrofit projects where existing conventional detector wiring must be integrated with modern addressable panels.
• Available in multiple mechanical and certification variants to suit varied regulatory and environmental requirements.

Use cases and scenarios where the product excels

The CHQ‑DZM(SCI) shines in situations where project constraints, existing wiring or regulatory environments require conventional detector circuits to be brought onto an addressable loop with minimal address consumption and solid fault management. Typical applications include:

• Refurbishment and retrofit projects— older buildings often have multiple conventional detector circuits. Using the CHQ‑DZM(SCI) allows two conventional loops to be reported via one ESP address, reducing panel programming complexity and preserving much of the existing wiring.
• Small to medium installations— for sites that need to monitor a couple of conventional zones without wasting address capacity, the dual‑zone interface is an efficient option.
• Environments requiring circuit protection— where cable damage or interference is a risk, the integral SCI provides fast isolation of short faults so the rest of the loop remains operational.
• Specialist installations— IS and HFP/marine/rail variants allow use in hazardous areas, marine vessels or rail rolling stock where certified equipment is mandatory.
• Contractor convenience— installers benefit from DIL addressing, compact form factor and flexible mounting options (module, DIN‑rail/boxed), making it quicker to configure and commission systems.

Comparisons with similar products in the market

When evaluating dual‑zone conventional‑to‑addressable interfaces, several factors typically guide the choice: address efficiency, monitoring capability, isolation features, variant availability and overall cost. Here’s how the CHQ‑DZM(SCI) compares in general terms with other approaches or competing modules:

• Dual‑zone vs single‑zone modules— single‑zone interfaces dedicate one ESP address per conventional circuit. Dual‑zone modules like the CHQ‑DZM(SCI) halve address usage per circuit pair, which is valuable when panel address capacity is limited. The trade‑off is that two physical zones share one logical address, so panel indication may be less granular unless the panel supports sub‑zone reporting.
• With vs without SCI— some lower‑cost interfaces omit short‑circuit isolation. The CHQ‑DZM(SCI) includes an integral SCI, improving fault tolerance and making it a better choice for installations with long cable runs or where continuity protection is important.
• Manufacturer ecosystem— Hochiki’s ESP protocol and product ecosystem are well‑established in commercial installations. Choosing a Hochiki module typically ensures strong compatibility and straightforward commissioning with Hochiki ESP panels compared with third‑party modules that may require extra validation.
• Certified variants— the availability of IS and HFP/marine options makes the CHQ‑DZM(SCI) more versatile for regulated industries than generic modules that lack these approvals.

Ultimately, the best choice depends on project priorities: if you need maximum address economy and enhanced wiring protection on a Hochiki ESP network, the CHQ‑DZM(SCI) is a compelling option. If you require per‑zone addressing for each conventional loop for site map granularity, a single‑zone interface may be preferable despite higher address use.

Customer testimonials and installer feedback

Official, verifiable public customer testimonials for specific module SKUs are limited in publicly available sources. However, feedback commonly reported in installer forums and by fire‑systems professionals about dual‑zone Hochiki interfaces typically highlights these points:

• "Easy to address and configure — DIL switches make commissioning quick and predictable."
• "The integral SCI is a practical feature — reduces downtime when wiring issues occur."
• "Good support from the Hochiki ecosystem — compatibility with ESP panels removes a lot of guesswork during integration."
• "Variants for IS and marine use are especially useful on regulated projects where certified hardware is mandatory."

If you need documented, site‑specific testimonials, ask suppliers for reference projects or case studies where the CHQ‑DZM(SCI) has been used — many distributors and manufacturers can share anonymised project references or put you in touch with installers who have hands‑on experience.

Installation, safety notes and pricing

Install only by qualified fire alarm engineers and always confirm the exact variant before wiring. The module requires a separate24 V DC auxiliary supplyand correct EOL resistor values, wiring capacitance/resistance limits and wiring diagrams must be followed exactly. Approvals and maximum detector counts vary between the standard, IS and HFP/marine/railway variants — consult the official datasheet and installation manual for compliance details (CE/UKCA and specific sector approvals).

From a commercial perspective, the product offers strong value: a cost price entry of around£105.12and a suggested retail price of around£129.99(price guidance varies by distributor and region). Given its address efficiency, fault‑tolerance features and variant flexibility, the CHQ‑DZM(SCI) typically delivers a good return on investment for projects that need to integrate conventional loops into an ESP addressable network.

Conclusion — why this product is a great choice

The Hochiki CHQ‑DZM(SCI) Dual‑Zone Detector Monitor Interface is a practical, feature‑rich module for contractors and system designers who need to bring conventional detector circuits onto a Hochiki ESP addressable network without wasting loop addresses. Its combination of two independently monitored zones, full open/short detection, integral short‑circuit isolation and multiple certified variants makes it a versatile solution for refurbishment, small‑to‑medium installations and specialist regulated environments.

Key strengths include clear installation workflows (DIL addressing), robust fault management through SCI and monitoring, and strong compatibility within the Hochiki ESP ecosystem. Where address economy and wiring resilience matter, the CHQ‑DZM(SCI) stands out as a well‑considered choice. As always, ensure you select the correct variant for your regulatory environment and consult the official datasheet and qualified installers for safe, compliant installation.