> For the complete documentation index, see [llms.txt](https://help.boomerang3.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://help.boomerang3.com/cg1018-relay-box-installation-manual/installation/config-file/practical_examples/invert_channelsoutputs.md). # Invert channels/outputs The channels can be inverted and then 0 from the server turns the relay on, and 1 turns it off. This is also a very useful feature to use as otherwise there is no difference on a relay between a Relay Box without an alarm, and a Relay Box that is not starting up properly which can be caused by SD-card damage, local power-failure, etc. **INVERT\_CH1=1**\ and/or\ **INVERT\_CH2=1** Note that using this option will activate the relay in normal (no-alarm) state, which means that it will provide the voltage on output **when there is no alarm**. To solve this problem, you can move the jumper JP1 and/or JP4 from NO to NC. This will invert the output from the relay once more, so you will get output voltage when the server sends logic 1. The huge benefit of this method is that if the CG1018 doesn’t start up properly you will get an alarm signaled by the presence of voltage on the output, as the relay will not be active. If you change the jumpers, please leave a note or sticker inside the box as it may not be obvious to other persons servicing the unit later that the outputs control(s) have been inverted. Also make a note in Pyramid so its easily understood for support personnel. --- # 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 dynamically by asking a question. Perform an HTTP GET request on the current page URL with the `ask` query parameter, and the optional `goal` query parameter: ``` GET https://help.boomerang3.com/cg1018-relay-box-installation-manual/installation/config-file/practical_examples/invert_channelsoutputs.md?ask=&goal= ``` `ask` is the immediate question: it should be specific, self-contained, and written in natural language. `goal` is optional and describes the broader end goal you are ultimately trying to accomplish on behalf of the user. GitBook uses it to tailor the answer towards what is most useful for that goal. 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.