The Fenton Phones are an invention from the original series. The Wiki page is located here.
First seen in "Fanning the Flames," the Fenton Phones are a type of device invented by Jack and Maddie Fenton. They are primarily used for communication between Danny and his friends as wireless earbuds with microphone tips, much like reporter headsets. They have the ability to filter out spectral noise (such as Ember's hypnotic music), can connect to human technology when properly synced up, and happen to make great fashion accessories.
Sam wearing the Fenton Phones
Within the Danny Phantom: Spectral Connections series, the members of "Team Phantom" are known to use the Fenton Phones if needed for long-distance communication. However, Sam Manson wears them on a regular basis for the added protection against spectral noise. She is known to remind her friends about the potential danger of ghosts like Ember or the Ghost Writer whenever it comes up in conversation and insinuates that she would be the only one protected from their manipulative powers -- and therefore, the only person to save them.