The NMF3000 and the NMF3010 are a dual-stage, differential line ESD and filtering protection scheme for input signals into portable devices. The NMF3000 is the first stage and is located at or very near to the interface to the outside world. It provides the high-level ESD protection as well as the initial filtering of incoming audio signals. The NMF3010 is the second stage and provides additional signal filtering. This second stage can be placed some distance away from the first stage to allow for effective filtering across extended distances.