> For the complete documentation index, see [llms.txt](https://docs.holybro.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.holybro.com/gps-and-rtk-system/h-rtk-unicore-um982/factory-setting-and-com-port-allocation.md). # Factory Setting and COM Port Allocation ### *Resetting to Holybro Factory Configuration* Using [Uprecise](/gps-and-rtk-system/h-rtk-unicore-um982/download.md#unicore-uprecise), type the following commands, followed by ENTER on your keyboard, into the configuration command line: * FRESET * GPGGA COM1 0.2 * GPRMC COM1 0.2 * AGRICA COM1 0.2 * GPGSA COM1 0.2 * GPGST COM1 0.2 * UNIHEADINGA COM1 0.2 * config com1 230400 * saveconfig ### Default COM Port Allocation UM982 has three COM (also called UART) ports. The connection relationship of these three COM ports in hardware is as follows: * COM1 <-> 10pin GH interface, connect to flight control * COM2 <-> 6pin GH interface, * COM3 <-> USB to UART chip <-> USB port In the factory default configuration, only COM1 port has GPS message output, COM2 and COM3 do not have GPS message output. (The fewer output messages, the lower the power consumption, which also helps to improve the receiving sensitivity of the module) ### Getting Data from USB Port If user connects to Uprecise through the USB port and wants to see the real-time information of GPS satellite search, one needs to enter the following command in the command line box after connecting: * GPGGA COM3 1 * GPRMC COM3 1 * AGRICA COM3 1 * UNIHEADINGA COM3 1 * saveconfig --- # 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://docs.holybro.com/gps-and-rtk-system/h-rtk-unicore-um982/factory-setting-and-com-port-allocation.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.