The name is a survival from the first era of fast international communication. Before the cable, the rate between London and New York depended on how long a ship took to cross; after it, the two markets could quote each other within minutes.
Cable is known for wide daily ranges relative to EUR/USD, driven by Bank of England policy, UK inflation and growth data, and the pound's sensitivity to risk sentiment. Its spread is typically a touch wider than fiber.
Example: GBP/USD moves from 1.2650 to 1.2790 over a Bank of England decision day, a 140-pip range. On a standard-lot that is $1,400 between the extremes.
Related: currency-nickname, fiber, major-pairs, indirect-quote