Skype would be considered the channel.
Interpersonal communication is the process of exchanging information between two or more people. In order for the process to be effective, communication channels need to be established. A channel is considered the way or tool through which the message or information is transmitted. In this case, Skype is considered the channel, the medium through which Amelia and her granddaughter can have a conversation similar to a "face-to-face" conversation.
