Convert from em to cable [U.S.]

Unit Definition (em)
The em is a printer's unit of relative distance. One em is the height of the type size (in points) being used. If 12 point type is being set, then one em is 12 points, and so on.

Unit Definition (cable [U.S.])
The cable is a unit of distance formerly used at sea. The traditional U.S. cable was equal to 120 fathoms, 720 feet, 0.1185 nautical mile, or about 219.4 meters. The British Admiralty, in 1830, defined the cable to equal exactly 0.1 nautical (Admiralty) mile, which is 608 feet or about 185.3 meters. The cable is also sometimes now defined as a metric cable, which is equal to exactly 200 meters.