| 摘要 |
PROBLEM TO BE SOLVED: To facilitate proper connection of a plurality of telephones or data communication units, etc., to one telephone line. SOLUTION: A telephone circuit 14 comprises: a telephone line connected via first switching means 12, 13; external unit terminals 27 connected to a telephone line via second switching means 23, 25; a means 26 for detecting acquisition of a telephone line by a unit connected to the external unit terminal 27; and a control means 15 which disconnects the first switching means 12, 13, while this detecting means 26 detects the line acquisition, disconnects the switching means 24, 25, while the telephone circuit 14 detects the telephone line acquisition; and sets both switching means 12, 13; 24, 25 to connected states, when either does not detect the line acquisition.
|
