To connect a standard AV connection to the television you would need a Phono adapter. For more information on this please use this link: https://support.vizio.com/s/article/Phono-Port-FAQ?language=en_US.
This television does not have a built in Spectrum application. We are continually evaluating new applications for addition to the SmartCast screen. In the meantime, you can cast any of the thousands of Chromecast enabled applications or Airplay content to the television from your mobile device.