How do I connect a UDACT to the NFS2-640 for central station monitoring?

NotifierNFS2-640Mar 23, 2026
0

To connect a UDACT or UDACT-2 to an NFS2-640 for central station monitoring, wire the communicator to the panel's EIA-485 ACS port and provide non-resettable power. This application requires 24 hours of standby power and 5 minutes of alarm power (Page 49) [1].

  1. Connect Power: Wire the UDACT to the FACP's non-resettable 24VDC power terminals (Page 49) [1].

  2. Connect Communication: Wire the supervised EIA-485 (ACS Mode) loop from the FACP to the UDACT (Page 49) [1].

  3. Install Termination: If the UDACT is the last or only device on the EIA-485 line, install a 120-ohm End-of-Line resistor (P/N 71244) across TB1 terminals 3 and 4 (Page 49) [1].

  4. Connect Phone Lines: Connect the UDACT to two supervised telephone lines using the provided ferrite cores (P/N 29090) (Page 49) [1].

  5. Verify Grounding: Ensure the FACP cabinet has a solid earth ground connection (Page 49) [1].

AI-generated — verify against your panel's documentation and applicable codes (NFPA 72, local AHJ).

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