{"product_id":"3-rs485b-edwards-est3-network-communications-card-class-ab-network-class-b-audio","title":"3-RS485B | Edwards EST3 Network Communications Card, Class A\/B Network \u0026 Class B Audio","description":"\u003ch4\u003eDescription \u003c\/h4\u003e\n\u003cp data-end=\"396\" data-start=\"144\"\u003eThe 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.\u003c\/p\u003e\n\u003cp class=\"\" data-end=\"574\" data-start=\"284\"\u003e \u003c\/p\u003e\n\u003cp class=\"\" data-end=\"574\" data-start=\"284\"\u003e \u003c\/p\u003e\n\u003ch4\u003eTechnical Specifications \u003c\/h4\u003e\n\u003ctable\u003e\n\u003ctbody\u003e\n\u003ctr\u003e\n\u003ctd\u003e\u003cstrong\u003eCondition\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd\u003eNew\/Never Used Surplus\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e\u003cstrong\u003eBrand\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd\u003eEdwards\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e\u003cstrong\u003eCategory\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd\u003eComputer\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e\u003cstrong\u003ePart Number\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd\u003e3-RS485B\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e\u003cstrong\u003eSubcategory\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd\u003eCommunication Card\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e\u003cstrong\u003eMounting\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd\u003eDirectly on 3-CPU1\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e\u003cstrong\u003eVoltage\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd\u003e24 VDC\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e\u003cstrong\u003eCurrent (Standby)\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd\u003e98 mA\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e\u003cstrong\u003eCurrent (Alarm)\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd\u003e98 mA\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e\u003cstrong\u003eNetwork Configuration\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd\u003eClass A (Style 6) or Class B (Style 4)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e\u003cstrong\u003eAudio Configuration\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd\u003eClass B (Style 4)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e\u003cstrong\u003eIsolation (Network)\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd\u003ePort A not isolated, Port B isolated\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e\u003cstrong\u003eIsolation (Audio)\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd\u003eAIN\/A BIN isolated, AOUT\/BOUT not isolated\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e\u003cstrong\u003eMaximum Wire Size\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd\u003e18 AWG (0.75 mm²) minimum twisted pair\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e\u003cstrong\u003eMaximum Circuit Length\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd\u003e5,000 ft (1,524 m) between any three panels\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e\u003cstrong\u003eCircuit Resistance\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd\u003e90 Ω maximum\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e\u003cstrong\u003eCircuit Capacitance\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd\u003e0.3 µF max (network), 0.09 µF max (audio)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e\u003cstrong\u003eNodes Supported\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd\u003eUp to 64 panels\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e\u003cstrong\u003eMedia Options\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd\u003eCopper or fiber with 3-FIBMB\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e\u003cstrong\u003eOperating Temperature\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd\u003e32°F to 120°F (0°C to 49°C)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e\u003cstrong\u003eHumidity\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd\u003e0–93% non-condensing\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e\u003cstrong\u003eApplication\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd\u003eNetwork and audio communication in EST3 systems\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e\u003cstrong\u003eWeight\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd\u003e0.25 lbs\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/tbody\u003e\n\u003c\/table\u003e\n\u003cp\u003e \u003c\/p\u003e\n\u003cp\u003e \u003c\/p\u003e\n\u003ch4\u003eInformation About \u003cspan data-sheets-root=\"1\"\u003e3-RS485B\u003c\/span\u003e\n\u003c\/h4\u003e\n\u003cp\u003eThe 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.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eKey Features:\u003c\/strong\u003e\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003eNetwork Communications Interface: Provides connectivity between EST3 network nodes.\u003c\/li\u003e\n\u003cli\u003eClass A\/B Network Support: Configurable for Class A (Style 6) or Class B (Style 4) circuits.\u003c\/li\u003e\n\u003cli\u003eAudio Circuit: One Class B digitized audio circuit for message and paging distribution.\u003c\/li\u003e\n\u003cli\u003eMessage Re-Transmission: Extends circuit length by forwarding network signals to the next node.\u003c\/li\u003e\n\u003cli\u003eExtended Network Reach: Supports up to 64 nodes and long wiring runs across large facilities.\u003c\/li\u003e\n\u003cli\u003eFail-Safe Protection: Direct-connect ports maintain communication if the card or CPU fails.\u003c\/li\u003e\n\u003cli\u003eFiber Compatible: Works with the 3-FIBMB for fiber optic media connections.\u003c\/li\u003e\n\u003cli\u003eCompact Mounting: Installs directly onto the 3-CPU1 processor module.\u003c\/li\u003e\n\u003cli\u003eElectrical Supervision: Provides isolated and non-isolated network\/audio port configurations.\u003c\/li\u003e\n\u003cli\u003eReliable Performance: Designed for life safety applications requiring uninterrupted communication.\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp\u003eThe 3-RS485B delivers the reliability and fault tolerance required for network and audio communication in Edwards EST3 systems.\u003c\/p\u003e","brand":"Edwards","offers":[{"title":"Default Title","offer_id":49105180197120,"sku":"3-RS485B","price":374.85,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0388\/5331\/2557\/files\/s-l1600_b6c27ce7-1717-4b0d-b660-1f04471a1c41.webp?v=1785541988","url":"https:\/\/alotechparts.com\/products\/3-rs485b-edwards-est3-network-communications-card-class-ab-network-class-b-audio","provider":"Alo Tech Solutions","version":"1.0","type":"link"}