Model Number Explanation

05704: System 57 / 5704 series (fire & gas detection system)

A: Standard card assembly

0121: Quad relay interface card (4 × SPDT)

Technical Specifications

Relay Channels: 4 × independent SPDT (Form C)

Contact Rating: 5 A @ 250 VAC / 30 VDC (resistive load)

Isolation: Galvanic isolation between system and relay contacts

Power Supply: 18–32 VDC (nominal 24 VDC, backplane‑fed)

Power Consumption: 1 W typical; 1.7 W maximum

Operating Temperature: −20°C to +60°C

Humidity: 5–95% RH (non‑condensing)

Form Factor: 3U × 1” wide rack‑mount card (19” subrack)

Dimensions: 110 × 53 × 30 mm (H×W×D)

Weight: ~0.23 kg

Certifications: CE, TUV, UL 508, CSA

Key Features

Four isolated relays: Independent SPDT outputs for up to four external devices

Galvanic isolation: Protects system electronics from external voltage/circuit noise

Hot‑swap capable: Insert/remove without powering down the rack

LED status indicators: Per‑relay LEDs for power and actuation status

Expandable output: Ideal for systems needing more alarm/control points than base cards provide

Applications

System Role: Relay output expander for System 57 fire/gas detection racks

Industries: Oil & gas, petrochemical, power, pharmaceuticals, water treatment

Use Cases:

Driving external alarm beacons, horns, or sirens

Controlling shutdown valves, dampers, or fans

Annunciating alarms in remote control rooms

Interfacing with third‑party panels (fire, security, BMS)

Compatibility

System: Honeywell System 57 (5704 fire detection, 5701 gas detection)

Backplane: Standard 19” subrack backplane (24 VDC power + data)

Replacement: Direct drop‑in replacement; obsolete (EOL), available as refurbished/used

Quick Note

This is a relay output card, not a control or input card. It does not process gas/fire signals—only provides isolated relay outputs based on system commands.