This cable expands every synth without a noise generator but an external audio input and a 5V source at the tip of a socket (e.g. an expression pedal input), and gives you digital noise. Initially the cable had been developed as an expansion for the Moog Little Phatty & Minitaur, but it also works with other synths.

The Hirlostek needs to be provided with 5V voltage - a circuit inside the bigger plug generates a bright digital noise that you can use as an audio or modulation source. The narrower plug carries the noise signal and is to be connected either with an audio input or a CV input.