Will Time Capsule back up IPhone/IPad?

No. They are backed up by iTunes.

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Unfortunately, it's not possible to back up an iPhone, iPod touch or iPad onto a Time Capsule. The Time Capsule is only officially compatible to back up Macs with Time Machine, but you can use it to store other files or back up PCs

Will Time Capsule back up IPhone/IPad?

The iPhone and iPad back up to iTunes on your Mac. Then, when your Mac backs up to the Time Capsule, the iOS backups are copied over as well.

Or

The iPhone and iPad can backup to iCloud

The iPhone and iPad cannot backup directly to the Time Capsule. See this Apple Support document for more details on backups.

http://support.apple.com/kb/HT4199