Friends – the United States, sitcom. (Season 3 Episode 22)
Rachel: Oh, Phoebe, are you still on hold? I was supposed to call my Dad back like two hours ago.
Phoebe: Oh, yeah, he clipped on, he said call him as soon as you get a chance, he’s at Flimby’s.
According to the subtitle I am watching the episode with it is "clicked on"
Either ways, what does it mean? I didn't find any meanings that relates in the web for either! Is it a slang word? (Though even that has a dictionary nowadays)