> For the complete documentation index, see [llms.txt](https://mycroft-ai.gitbook.io/mark-ii/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://mycroft-ai.gitbook.io/mark-ii/advanced/hardware-features.md). # Hardware Features * The 10 pin adapter on the rear of your Mark II provides easy access to the Raspberry Pi GPIO pins 1, 7, 14, 15, as well as the I2C bus on GPIO 2 & 3. There is also a ground, a +3V3, and two +5V pins. The connector is pin compatible with Raspberry Pi extension modules using I2C or UART. We’re excited to see what the community comes up with for innovative uses of this port. * Replaceable Raspberry Pi - upgrade to 4gb or 8gb if you swap out the raspberry pi * 2 x USB 3.0 and 2 x USB 2.0 ports. * The SJ201 is the only voice development board that includes Audio input DSP, LEDs, buttons, and high end amplified audio output for the Raspberry Pi. This makes it the most customizable Voice Assistant hardware platform that is ready to use out of the box. * Hackable mounting holes on the back of the Mark II can be used for modification. Designed to accept the popular M2.5 sized screw, these holes can be used to extend the audio port, or make your Mark II the head of a robot! * The Mark II is designed to be disassembled with just a phillips #1 (ph1) screwdriver. A long reach version is required 4” (100 mm) to reach some screws. * We strived not to use any permanent bonding adhesives that would make it difficult to repair. There is hot glue between the two halves of the Audio Chamber. Hot glue is also used to create a seal where the wires pass through the Audio Chamber. In both cases the Hot glue can be removed and reapplied or repaired. * The Mark II can be modified to use a Real Time Clock * The Mark II can be upgraded to output via HDMI --- # 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://mycroft-ai.gitbook.io/mark-ii/advanced/hardware-features.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.