Summarize this article in one sentence.
This helps rule out problems associated with a faulty cable or port. Outdated software can interfere with your computer's ability to detect your iPad. This refreshes both devices and helps resolve connectivity problems. Repositories are hosted by third parties independent of Cydia, and are not guaranteed to work at all times.
Use a different USB cable or USB port if iTunes doesn't recognize your iPad. Install available updates for iTunes, your iPad, and computer if your iPad still isn't recognized by iTunes. Restart your iPad and computer if iTunes still cannot recognize the iPad. Try adding a different repository to Cydia on your jailbroken iPad if the repo fails to work and you cannot download free apps.