Answer:
It was actually one of the first punch card "computer" systems. A punch card would be inserted into the machine and it would weave accordingly.
It actually took a deck of several hundred or thousand punched cards to specify one weave pattern. Each card specified the up/down positions of each of the lengthwise threads for a single pass of the crosswise thread. In other words, if a certain textile needed 2087 crosswise thread passes to create the weave pattern, a deck of 2087 punch cards was needed. Each hole in the card corresponded to on lengthwise thread.