The cable comes through the backing plate on the left, and the end goes through the emergency lever on the bottom right. You have to push the spring on the cable back a little and the lever has a fork in it that goes around the cable. The lever then goes up and behind the shoe. It has a hook at the other end that goes through a hole in the brake shoe near the top. The emergency strut makes sure that both shoes move together when the cable gets pulled. It is shown at the top of the picture going horizontal with the spring in the front.
