Multiple remote points control on/off switch

摘要

Sometimes, you need to remotely turn on or off a two-state system, such as a light, from multiple points. You could connect simple pushbutton switches in parallel to a single-line bus. However, if the bus simply controls a toggle flip-flop, the system must know its current state to positively ensure the new, desired state. For example, if you want to make sure the light is on, you must have visual or electrical feedback via a second line before deciding whether to toggle the flip-flop. Also, bounce-free pushbutton switches are necessary.