I've seen these advertised on TV.
It's nothing more than a small plug inserted into the phone with a magnet and a set of contacts. The cable has a similar magnet (I think) and a set of pins. When the two are brought close together, the magnets attract and pull the two parts together, with the pins being pulled onto the contacts.
It's a cute gimmick, but it does allow for a cable to be yanked and the magnets will give way rather than the socket getting hammered.