Example with a context (Java: A Beginner's Guide, 6th Edition by Herbert Schildt):
OOP is a powerful way to approach the job of programming. Programming methodologies have changed dramatically since the invention of the computer, primarily to accommodate the increasing complexity of programs. For example, when computers were first invented, programming was done by toggling in the binary machine instructions using the computer's front panel.
I don't think I comprehend that part well enough. To toggle something basically means to switch it back and forth between two different states. But here, I'm really at a loss as to how I should interpret the action of toggling in this context. Plus, the preposition in also throws me off a little bit.