Because it was not enough to have cell phone coverage inside the subway and on the mountaintop, Korean telecom companies installed relays on lighthouses so that there will be cell phone reception 50 kilometers (around 30 miles) off the coast.

The logical next step? Waterproof cell phone to be used as a flotation device.

50km 밖 바다에서도 통화 가능 [Dong-A Ilbo]