SBUS Fiber Optic Revisited: FAQs

sbus_webinar_screenI conducted a webinar on November 16, 2015, titled Powerful and Simple! Flexible Design with SBUS and Fiber Optic to provide an overview of the Silent Knight addressable SBUS devices and how they provide flexibility for a variety of applications. I also presented the SK-F485C SBUS to Fiber Optic converter. This product provides a solution to the high risk of lightning damage and ground faults that often occur with wire runs between buildings.

Thank you for those who were able to attend this webinar. There were excellent questions and comments and I would like to address some of them in this blog:

  • A popular question centered on cascade and daisy-chain wiring of multiple SBUS devices. SBUS devices are addressable and provide flexible wiring configurations. Daisy chain, T-Tapping, and Home Run wire configurations are all acceptable methods. The fire alarm control panel will properly annunciate and report trouble events if there is a wire break with any of these methods.
  • Another popular question related to wire type and distances. Specifications call out for wire to be from 14 AWG to 22 AWG with a possible distance up to 6,000 feet. Wire can be of any type that meets NEC 760 fire power limited fire protective signaling cable.
  • Lastly, questions and observations arose about the specifications of the fiber optic cable. The SK-F485C uses 62.5 micron multi mode fiber optic cable at 115.2K bits/second. Fiber connections are ST connectors and the cable distance is up to 1 mile (5,280 feet).

If you have any questions or need assistance with an application, please contact the Silent Knight Applications department at 1-800-446-6444 or

Do you know that you can download and view this and other previously held Silent Knight webinars? Click here to access our webinar library page.


About the Author
Mark Indgjer is a Product Marketing Manager with Silent Knight.  Mark joined Silent Knight in 1988 and is responsible for new product development, product marketing and much more.  Mark is also NICET Level II certified.​

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