> For the complete documentation index, see [llms.txt](https://headtracker.gitbook.io/head-tracker/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://headtracker.gitbook.io/head-tracker/getting-started/wiring/option-2-wired/pulse-position-modulation-ppm.md). # Pulse Position Modulation (PPM) PPM output is by far the most widely supported format for a trainer connection. Almost every radio that has a trainer port will support it. There are a few options with PPM you can choose * Output Pin * Channels * The Frame Length * Sync Pulse * Inverted The default settings should work for most radios. You may need to play with the sync pulse time in the GUI so your radio can pick it up. Also try inverted too if you can't get a connection. Many radios use a 3.5mm headphone jack for their trainer connection. You can cut an old headphone cable to use if this is your case. Most are a 3 pin device, you will need to determine what the tip wire is and the base ground wire. See the wiring diagram for details. Always refer to your manual of your radio for the proper plug and setup. {% hint style="danger" %} !!! Some radios have been found to output too high of a voltage on the trainer port. So far just the **Spektrum DX18**. This is causing the Nano33BLE to fail. Please do not use with this radio until a solution is posted. {% endhint %} ### Radio Setup There are too many radios to list them all but if your using OpenTX or EdgeTX, you only need to set the Trainer mode to Master/Jack at the bottom of your model page. Then set the channels you want to use as TRx under the mixes page. You can verify the channel data the same way as you would with SBUS ![Open TX](/files/-Md81dX93EvpyB_xN_xP) ![Edge TX](/files/-Md81Zax_h54waeDbmF0) For other radios please refer to your manual. --- # 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://headtracker.gitbook.io/head-tracker/getting-started/wiring/option-2-wired/pulse-position-modulation-ppm.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.