By age eight your child should know how to place a collect call. He should know how to spell his name, his home phone number and address, parents' work numbers, and whom to call in an emergency. If that's too complicated — and complicated it is if you're trying to teach about the need to dial the area code when calling from certain long-distance locations — be sure he knows how to dial the operator, ask to be connected with the police, and explain his dilemma so you can be contacted. Your tween needs to know how to spell your last name, and the name of his city and state. As an added precaution, keep your telephone number listed.