The US’s two largest cablecos, Comcast and Charter Communications, agreed last year to cooperate on developing mobile services and platforms, raising the spectre of a significant challenger to the established MNOs. The two companies, which are both launching into the cellular and quad play markets via MVNO deals with Verizon, have now extended their cooperation to the back office. The two cable operators are increasingly serious about adding wireless services to their portfolio – initially through their extensive CableWiFi network of hotspots and homespots, and now through their MVNOs. They are active in 5G tests, Comcast acquired spectrum in the 600 MHz auction, and they are repeatedly tipped to be possible bidders for one of the smaller MNOs, or even…