The M2BUS method, that uses only a single pin, is a half-duplex method used also in older Nokia phones. With M2BUS it is possible to interface with almost all Nokia mobile phones for service and adjustment purposes. The FBUS is a newer solution and offers high-speed full-duplex communications link between the phone and the computer. The service and adjustment operations, which are traditionally made over M2BUS, are available also via FBUS, but usually much faster.