Jax the cat knows that when the phone rings, it's impolite not to answer.
When the phone rings, this attentive feline rushes to greet the unknown caller before realizing ... well, that he can't talk. Jax has no idea what to do, so he just lets the phone fall to the floor, unable to respond to the caller.
It's okay, Jax — everyone knows it's the thought that counts when it comes to phone calls. Right?