ASIO is the only way to get low-latency audio on Windows!
ASIO is a computer sound card driver protocol for digital audio specified by Steinberg, providing a low-latency and high fidelity interface between a software application and a computer's sound card. More to the point, it's the only way to get low-latency audio on Windows. Lots of devices have ASIO drivers, for example many devices made by top audio companies like Universal Audio, Presonus and Focusrite.
You may have heard of a software application called ASIO4ALL, which claims to provide ASIO support for any audio device on Windows. Not only is ASIO4ALL extremely hard to use, our experience has repeatedly shown that ASIO4ALL does not work well, so we do not recommend using it.
We recommend that Windows users stick with one of the high quality and well tested audio interfaces listed here. If you have or would like to try another audio interface, please make sure that the manufacturer provides ASIO drivers for it. Although it can sometimes work, you are unlikely to have a good experience using JackTrip with ASIO4ALL, or another one of the audio APIs built-into Windows (DirectSound, MME etc).