









3-RS485B | Edwards EST3 Network Communications Card, Class A/B Network & Class B Audio
- Regular price
- $419.00
- Sale price
- $419.00
- Regular price
-
$0.00
Couldn't load pickup availability
Do you need help?

Product Description P/N: 3-RS485B
Description
The Edwards 3-RS485B is a network communications card designed for EST3 fire alarm and emergency communication systems. It provides Class A or Class B circuits for network communications and an additional Class B circuit for digitized audio signals. The 3-RS485B mounts directly to the 3-CPU1 and retransmits network messages to extend wire run distances and ensure reliable inter-panel communication.
Technical Specifications
Condition | New/Never Used Surplus |
Brand | Edwards |
Category | Computer |
Part Number | 3-RS485B |
Subcategory | Communication Card |
Mounting | Directly on 3-CPU1 |
Voltage | 24 VDC |
Current (Standby) | 98 mA |
Current (Alarm) | 98 mA |
Network Configuration | Class A (Style 6) or Class B (Style 4) |
Audio Configuration | Class B (Style 4) |
Isolation (Network) | Port A not isolated, Port B isolated |
Isolation (Audio) | AIN/A BIN isolated, AOUT/BOUT not isolated |
Maximum Wire Size | 18 AWG (0.75 mm²) minimum twisted pair |
Maximum Circuit Length | 5,000 ft (1,524 m) between any three panels |
Circuit Resistance | 90 Ω maximum |
Circuit Capacitance | 0.3 µF max (network), 0.09 µF max (audio) |
Nodes Supported | Up to 64 panels |
Media Options | Copper or fiber with 3-FIBMB |
Operating Temperature | 32°F to 120°F (0°C to 49°C) |
Humidity | 0–93% non-condensing |
Application | Network and audio communication in EST3 systems |
Weight | 0.25 lbs |
Information About 3-RS485B
The 3-RS485B is part of the Edwards EST3 network communication family, enabling secure data and audio transfer between fire alarm control panels. Unlike the 3-RS485A, which offers two Class A audio circuits, the 3-RS485B provides one Class B audio circuit for system integration flexibility. The module supports up to 64 nodes across copper or fiber cabling, with the 3-FIBMB used for fiber communication. Fail-safe circuitry ensures continuous operation by automatically connecting input and output ports if the card or CPU fails, preserving critical communication pathways.
Key Features:
- Network Communications Interface: Provides connectivity between EST3 network nodes.
- Class A/B Network Support: Configurable for Class A (Style 6) or Class B (Style 4) circuits.
- Audio Circuit: One Class B digitized audio circuit for message and paging distribution.
- Message Re-Transmission: Extends circuit length by forwarding network signals to the next node.
- Extended Network Reach: Supports up to 64 nodes and long wiring runs across large facilities.
- Fail-Safe Protection: Direct-connect ports maintain communication if the card or CPU fails.
- Fiber Compatible: Works with the 3-FIBMB for fiber optic media connections.
- Compact Mounting: Installs directly onto the 3-CPU1 processor module.
- Electrical Supervision: Provides isolated and non-isolated network/audio port configurations.
- Reliable Performance: Designed for life safety applications requiring uninterrupted communication.
The 3-RS485B delivers the reliability and fault tolerance required for network and audio communication in Edwards EST3 systems.
Description
The Edwards 3-RS485B is a network communications card designed for EST3 fire alarm and emergency communication systems. It provides Class A or Class B circuits for network communications and an additional Class B circuit for digitized audio signals. The 3-RS485B mounts directly to the 3-CPU1 and retransmits network messages to extend wire run distances and ensure reliable inter-panel communication.
Technical Specifications
Condition | New/Never Used Surplus |
Brand | Edwards |
Category | Computer |
Part Number | 3-RS485B |
Subcategory | Communication Card |
Mounting | Directly on 3-CPU1 |
Voltage | 24 VDC |
Current (Standby) | 98 mA |
Current (Alarm) | 98 mA |
Network Configuration | Class A (Style 6) or Class B (Style 4) |
Audio Configuration | Class B (Style 4) |
Isolation (Network) | Port A not isolated, Port B isolated |
Isolation (Audio) | AIN/A BIN isolated, AOUT/BOUT not isolated |
Maximum Wire Size | 18 AWG (0.75 mm²) minimum twisted pair |
Maximum Circuit Length | 5,000 ft (1,524 m) between any three panels |
Circuit Resistance | 90 Ω maximum |
Circuit Capacitance | 0.3 µF max (network), 0.09 µF max (audio) |
Nodes Supported | Up to 64 panels |
Media Options | Copper or fiber with 3-FIBMB |
Operating Temperature | 32°F to 120°F (0°C to 49°C) |
Humidity | 0–93% non-condensing |
Application | Network and audio communication in EST3 systems |
Weight | 0.25 lbs |
Information About 3-RS485B
The 3-RS485B is part of the Edwards EST3 network communication family, enabling secure data and audio transfer between fire alarm control panels. Unlike the 3-RS485A, which offers two Class A audio circuits, the 3-RS485B provides one Class B audio circuit for system integration flexibility. The module supports up to 64 nodes across copper or fiber cabling, with the 3-FIBMB used for fiber communication. Fail-safe circuitry ensures continuous operation by automatically connecting input and output ports if the card or CPU fails, preserving critical communication pathways.
Key Features:
- Network Communications Interface: Provides connectivity between EST3 network nodes.
- Class A/B Network Support: Configurable for Class A (Style 6) or Class B (Style 4) circuits.
- Audio Circuit: One Class B digitized audio circuit for message and paging distribution.
- Message Re-Transmission: Extends circuit length by forwarding network signals to the next node.
- Extended Network Reach: Supports up to 64 nodes and long wiring runs across large facilities.
- Fail-Safe Protection: Direct-connect ports maintain communication if the card or CPU fails.
- Fiber Compatible: Works with the 3-FIBMB for fiber optic media connections.
- Compact Mounting: Installs directly onto the 3-CPU1 processor module.
- Electrical Supervision: Provides isolated and non-isolated network/audio port configurations.
- Reliable Performance: Designed for life safety applications requiring uninterrupted communication.
The 3-RS485B delivers the reliability and fault tolerance required for network and audio communication in Edwards EST3 systems.




