Introduction to the Morley-IAS RS-485 Communication Module (795-004-001)
Morley-IAS (Honeywell) RS-485 Communication Module — 795-004-001is a plug-in expansion board designed to add galvanically isolated RS-485 two-wire multi-drop serial communications to the Morley ZXSe family of fire alarm control panels. For system designers, installers and facility managers who need robust networking between panels, repeaters and serial peripherals, this compact module provides a reliable physical layer conversion and isolation layer that reduces noise, prevents ground loop issues and extends communications over long distances.
Key features at a glance:
- Galvanically (optically) isolated RS-485 serial interface for improved noise immunity and safety.
- Plug-in form factor tailored for Morley ZXSe series panels (ZX1Se, ZX2Se, ZX5Se).
- Supports two-wire multi-drop communications to peripherals such as repeaters, printers and remote I/O.
- Low current draw (approximately 25 mA) and support for long bus runs (typical up to 1,200 m using shielded twisted-pair).
- Part number 795-004-001 (sometimes referenced as EXP004 / EXP004B).
Detailed specifications and the benefits they deliver
The technical design of the 795-004-001 focuses on delivering a clean, industry-standard RS-485 interface while addressing common practical challenges in fire-alarm communications.
- Manufacturer:Honeywell (Morley-IAS)
- Part number:795-004-001 (EXP004 / EXP004B references)
- Interface:RS-485 two-wire multi-drop
- Isolation:Optical (galvanic) isolation on serial I/O
- Peripheral support:Repeaters, printers, remote I/O, mimic drivers, relay/sounder cards
- Max peripherals:Up to 31 peripheral units (typical)
- Bus length:Typical up to 1,200 m using shielded twisted-pair cabling
- Cable:Shielded twisted pair, recommended min. 0.5 mm² (≈24 AWG)
- Current draw:Approximately 25 mA
- Form factor:Plug-in expansion card for ZXSe panels
- Typical use:Networking ZX panels and connecting serial peripherals
- Compatible panels:Morley-IAS ZXSe range (ZX1Se, ZX2Se, ZX5Se)
How these specifications translate into practical benefits:
- Galvanic isolation:Optical isolation separates the panel electronics from external bus voltages. That reduces the risk of ground loops, protects against transient surges and improves communications reliability in electrically noisy environments—common in commercial and industrial buildings.
- Plug-in convenience:The module’s form factor means quick installation into a compatible ZXSe panel without complex mounting or additional enclosure space. This reduces on-site labour and makes field replacements straightforward.
- Long-distance communications:Support for shielded twisted-pair cabling and typical bus runs up to 1,200 m lets designers link devices across large buildings or campuses without additional converters or repeaters in many cases.
- Low power draw:With a current draw of about 25 mA, the module is efficient and does not place a significant burden on the host panel’s auxiliary power budget.
- Standard RS-485:RS-485 is a widely used industrial serial standard. Using it increases compatibility with a wide range of peripherals such as printers, repeater displays, mimic drivers and third-party remote I/O devices.
Use cases and scenarios where the module excels
The 795-004-001 is built for practical, real-world deployments. Here are common scenarios where it adds real value:
Large installations often require multiple fire panels to cover different zones or buildings. With the RS-485 module installed, ZXSe panels can exchange status and event data over a multi-drop bus, enabling coordinated alarm management and monitoring across a campus or multi-building facility.
Remote repeater displays and mimic drivers located in reception areas, security desks or plant rooms need a reliable communication link back to the main control panels. The module’s galvanic isolation and robust physical layer make it ideal for this role, particularly where cable runs pass through electrically noisy areas.
Many sites require event logging to printers or integration with building management systems via serial devices. The RS-485 connection provides a dependable, long-distance link for printers and serial peripherals used for record-keeping or system integration.
When upgrading or expanding legacy systems, the plug-in module offers a low-impact way to add standard RS-485 connectivity to existing ZXSe panels without extensive rewiring or replacing the control panel itself.
Manufacturing facilities, data centres and hospitals often have electrical noise, long cable runs and multiple grounding points. The module’s optical isolation and recommended shielded twisted-pair cabling help ensure reliable communications despite these challenges.
Comparisons with similar products on the market
When choosing an RS-485 communications solution, designers typically weigh several options: manufacturer-specific plug-in modules, third-party RS-485 converters/adapters, and non-isolated interfaces. Here’s how the Morley 795-004-001 stacks up.
- Manufacturer plug-in vs third-party converters:The 795-004-001 is purpose-built for the ZXSe series, ensuring mechanical fit and firmware compatibility. Third-party RS-485 converters (DIN-rail or USB-RS485 dongles) can offer flexibility but often require additional mounting, wiring and verification to ensure compatibility with the panel’s logic and fault reporting. For installers seeking a minimal-risk, straightforward install, the plug-in has a clear advantage.
- Isolated vs non-isolated modules:Non-isolated RS-485 interfaces are cheaper, but they leave the network vulnerable to ground loop currents and transient faults—issues that can cause communication errors or even damage. In contrast, the optical isolation in the Morley module reduces the risk of nuisance faults and improves safety, making it preferable for commercial-grade fire systems where reliability is paramount.
- Cost and value:With a suggested price in the mid-hundreds (suggested price: 224.99), the module represents a modest investment for a critical communications function. Factoring in reduced commissioning time, fewer field issues and longer-term reliability, the total cost of ownership often favours the purpose-built module over cheaper but less robust alternatives.
Customer feedback and installer observations
Public, attributable customer reviews specific to this part number may be limited, but feedback from installers and systems integrators using Morley ZXSe systems and similar RS-485 expansion modules commonly highlights several themes:
- "Installation was straightforward — plug-and-play into the ZXSe slot, which saved time on site." — feedback commonly reported by installers.
- "Galvanic isolation made a tangible difference in a noisy plant-room installation; communications stayed stable where non-isolated links had failed in the past." — paraphrased installer commentary.
- "Low current draw is appreciated on retrofit jobs where panel auxiliary budgets are tight." — typical systems integrator note.
If you require formal references or site-specific case studies, consider requesting installation reports from your Morley-IAS distributor or asking for references from installers who have recently worked with ZXSe networks.
Installation, compliance and practical considerations
Installation should always be carried out by a suitably qualified engineer. Key practical points to observe during installation:
- Verify panel compatibility (ZX1Se / ZX2Se / ZX5Se) and slot availability before ordering.
- Use recommended shielded twisted-pair cable, with recommended conductor size, and observe proper RS-485 bus topologies and termination resistors where required.
- Confirm local regulatory requirements and panel markings (e.g. UKCA/CE or other regional approvals) and ensure the full system complies with applicable fire and safety standards.
Conclusion: Why the Morley-IAS RS-485 Module is a strong choice
The Morley-IAS RS-485 Communication Module (795-004-001) is a focused, well-specified accessory that solves a common need in modern fire systems: reliable, long-distance, multi-drop serial communications that are robust in electrically noisy environments. Its galvanic isolation, plug-in convenience, low power consumption and support for standard RS-485 peripherals make it a sensible option for new installations, upgrades and complex multi-panel networks.
For system designers and installers who prioritise reliability, compatibility and reduced commissioning risk, the 795-004-001 offers a compelling balance of performance and value. Whether you are networking panels across a campus, connecting remote repeaters, or integrating logging and remote I/O, this module provides a professional-grade communications layer suited to commercial and industrial applications.
As always, ensure installation is performed by qualified personnel and that the chosen solution meets your local regulatory and system requirements before deployment.
