Question: What additional feature does the AirPort Time Capsule have over the Airport Extreme in the Apple network product line-up?
Sentence (from "AirPort Time Capsule"): The AirPort Time Capsule (previously known as just Time Capsule) is a wireless router sold by Apple Inc., featuring network-attached storage (NAS) and a residential gateway router, and is one of Apple's AirPort products.
Relevant evidence: No