# How-Tos - [Upgrading Board Firmware](https://docs.axsun.com/axsun-knowledge-base/how-tos/upgrading-board-firmware.md) - [Upgrading FPGA Bitstreams](https://docs.axsun.com/axsun-knowledge-base/how-tos/upgrading-fpga-bitstreams.md) - [Using AxsunOCTControl.dll in C++](https://docs.axsun.com/axsun-knowledge-base/how-tos/using-axsunoctcontrol.dll-in-c++.md): AxsunOCTControl.dll is a C#/.NET managed library. This document describes how to use AxsunOCTControl.dll from an unmanaged or native C++ application in Windows Visual C++. - [Operating a Variable Delay Line](https://docs.axsun.com/axsun-knowledge-base/how-tos/operating-a-variable-delay-line.md): This page describes how Standard OEM laser engines and Axsun Integrated Engines can operate a miniature motorized Variable Delay Line (VDL) if the optional driver electronics are installed. - [Using the Interface Board](https://docs.axsun.com/axsun-knowledge-base/how-tos/using-the-interface-board.md) - [Installing the PCIe Device Driver](https://docs.axsun.com/axsun-knowledge-base/how-tos/installing-the-pcie-device-driver.md): For driver versions v1440 and older on Windows OS. - [Using Bus Power for the PCIe DAQ](https://docs.axsun.com/axsun-knowledge-base/how-tos/using-bus-power-for-the-pcie-daq.md) --- # Agent Instructions: 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: ``` GET https://docs.axsun.com/axsun-knowledge-base/how-tos.md?ask= ``` The question should be specific, self-contained, and written in natural language. 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.