> For the complete documentation index, see [llms.txt](https://help.security.gallagher.com/knowledge-hub/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://help.security.gallagher.com/knowledge-hub/products/cc-hardware/perimeter-solutions/gallagher-fibre-transceiver.md). # Gallagher Fibre Transceiver Learn about Gallagher Fibre Transceiver variants, supported topologies, and HBUS communication. Gallagher Fibre Transceivers extend HBUS communication over fibre. They support two RS485 connections and three network topologies. N11/N12 transceiver unit ### Overview The transceiver carries two RS485 connections over fibre. A typical installation carries HBUS and LV Sync. This keeps high-voltage pulses synchronized across the site. ### Variants There are two variants * The N11 supports single-mode fibre. * The N12 supports multi-mode fibre. {% hint style="warning" %} N11 and N12 units are not interchangeable. Match the unit to the installed fibre cable type. {% endhint %} ### Installation Note [RS485 Fibre Tranceiver (N11 and N12)](https://media.gallagher.com/asset/0d883fb9-57a8-4f5c-ad0b-054cd5e78c9f/3E3227-Install-Note-RS485-Fiber-Transceiver.pdf) {% hint style="warning" %} Configuration and Installation should be done by an authorised Channel Partner. {% endhint %} ### Supported topologies * Point-to-point — two transceivers with a direct fibre link * Linear add/drop/repeat — a chain of transceivers with RS485 devices at each unit * Self Healing Ring (SHR) — a resilient ring that routes communication around a fibre break ![Basic fibre run architecture](https://328339335-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2F6bM8WhlBE9BYizPWJaPN%2Fuploads%2Fgit-blob-fc1b5dc2f05bbd2ba6fe42be07dc5b8eb7d6f1e4%2FSECHUB-FIBRE-05-basic-run-architecture.jpeg?alt=media) *** 🔗 **Related** * [Input and output (I/O) devices](/knowledge-hub/products/cc-hardware/input-and-output-io-devices.md) support HBUS communication. * [Perimeter Solutions](/knowledge-hub/products/cc-hardware/perimeter-solutions.md) include Fence Controllers. * [Controllers](/knowledge-hub/products/cc-hardware/controllers.md) connect at the head end of an HBUS run. * [Fibre Transceiver specifications](/knowledge-hub/products/cc-hardware/perimeter-solutions/gallagher-fibre-transceiver/fibre-tranceiver-switch-settings.md) lists variant and DIP switch details. --- # Agent Instructions This documentation is published with GitBook. GitBook is the documentation platform designed so that both humans and AI agents can read, navigate, and reason over technical content effectively. Learn more at gitbook.com. ## Querying This Documentation If you need additional information that is not directly available in this page, you can query the documentation by asking a question. Perform an HTTP GET request on the following URL with the `ask` and `goal` query parameters: ``` GET https://help.security.gallagher.com/knowledge-hub/products/cc-hardware/perimeter-solutions/gallagher-fibre-transceiver.md?ask=&goal= ``` `ask` is the immediate question: it should be specific, self-contained, and written in natural language. `goal` is what the user is ultimately trying to achieve, the reason they need the answer. Sharing it helps GitBook give you a better, more relevant answer. A goal is most helpful when it describes the outcome the user wants rather than restating the question. For example, with `ask=how do I create an API token`, a goal like `automate deployments from our CI pipeline` lets GitBook tailor the answer to that use case. The response will contain a direct answer to the question and relevant excerpts and sources from the documentation. Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.