# How-Tos

- [Upgrading Board Firmware](/axsun-knowledge-base/how-tos/upgrading-board-firmware.md)
- [Upgrading FPGA Bitstreams](/axsun-knowledge-base/how-tos/upgrading-fpga-bitstreams.md)
- [Using AxsunOCTControl.dll in C++](/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](/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](/axsun-knowledge-base/how-tos/using-the-interface-board.md)
- [Installing the PCIe Device Driver](/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](/axsun-knowledge-base/how-tos/using-bus-power-for-the-pcie-daq.md)