A "straight key" is the common telegraph key as seen in various movies. It was first developed with a telegraph key, however soon improved with telephones built in. Eaton had the telegraph key drive electromagnets that operated a relay. Subsequently, Dyston collapsed onto the telegraph key after he sent an incoherent message and died. The telegraph key often directly made and broke the 2,000 volt supply. When Dyston reached the telegraph key he managed to call for help. Examples of binding posts used during 19th century are telegraph key and blasting machine devices.