Television co-viewing series unit

摘要

A series unit capable of easily changing over a unidirectional state to/from a bidirectional state and easily judging which state the series unit is in, is provided. ;A high pass filter 9 and a changeover switch 5 are included, and an operating protrusion 5a of the changeover switch 5 is provided in a circular recess 10 of a panel 2 formed to surround an F-type terminal 4 provided on a front surface. A cylindrical adapter 6 inserted into the circular recess 10 is provided so as to operate the operating protrusion 5a. The adapter 6 has a notch 6a which is provided on one side portion of the adapter 6 and which does not press the operating protrusion 5a. By inserting the adapter 6 while rotating the adapter and changing an angle, a unidirectional state can be changed over to/from a bidirectional state. In addition, a mark 16a indicating a position of the operating protrusion 5a is provided on the panel 2 and a mark 15 indicating a notch position is provided on an end portion on a front surface of the adapter 6.