The invention relates to a method of transmitting teaching materials by means of an electronic data network, wherein a person to be taught is first shown the teaching material on a client computer system. The CPE device includes a user input device for receiving a user input specifying one or more channels for which closed caption information is sought. In response to the detection or sensing of the predetermined physical phenomenon, a signal is transmitted to a control unit in a communication device. First cam surfaces are affixed relative to the housing and second cam surfaces are movably mounted relative to the housing.