Protruding part of a mechanism body is connected to a base frame by screws, and other protruding part is connected to an auxiliary connecting metal fittings by the screws. The bolt is substantially located within the housing and is biased by the spring into an extended position. Each unit shift register in the odd and even drivers receives a selection signal in the second previous row and activates its own selection signal two horizontal periods later. In a preferred embodiment, the system receives a channel signal, detects a program start or stop marker within the signal, and controls the EPG or the recording device to perform acts corresponding to the detection of a start or stop instruction.