As I recall, there was a movie where someone was in jail, the CO dialed the phone number for their free phone call, and then when the CO locked the number pad a

As I recall, there was a movie where someone was in jail, the CO dialed the phone number for their free phone call, and then when the CO locked the number pad and left, the "hacker" immediately hung up and redialed a different number by tapping on the cradle switch. They might have just tapped 10 times (dial rotary-0) to get an operator and then requested manual completion of the call. I don't remember, exactly. I don't even know if you can still also do pulse dialing instead of solely DTMF dialing now.