Season 3 episode 2: Breaking Up Is Hard to Undo; Kelly leaves an angry answering machine message directed toward Zack which he plays for Slater in the boys locker room.
Season 2 episode 8: Rent - A - Pop; Zack comes to the realization that there is only one way to reach out to his father Derek: mobile to mobile.
Season 2 episode 8: Rent - A - Pop; Zack tries to have a serious confrontation with his father but Derek keeps getting distracted by phone calls.
Season 2 episode 4: Driver's Education; Zack tricks Screech into doing his Mr. Tuttle impersonation over the phone to stall Mr. Belding.
Season 1 episode 20: Screech's Birthday; The girls call Mr. Belding pretending to be a student who has multiple personality disorder and is lost in the mall.
Season 1 episode 11: The Friendship Business; Zack uses his cell phone to make an important business call while being filmed for "Lifestyles of the Rich and Shameless".
Season 1 episode 9: Pinned to the Mat; Zack calls Major Slater while eating a hot dog at The Max.
Season 1 episode 5: Screech's Woman; Zack calls Screech under the guise of Bambi unaware that Mr. Belding is in the bathroom with him.
Season 1 episode 3: The Gift; After losing a bet to Slater, Zack orders him a pizza.
...with the hottest peppers you can find!
Season 1 episode 3: The Gift; Zack attempts to dupe principal Belding and Mr. Testaverde via impersonating phone calls to both parties.
Season 1 episode 3: The Gift; Zack calls the race tracks after Screech possesses the power to see the future.