| 摘要 |
When a two-way call connection state, which is between a customer terminal connected to an outside line (3) side of a private branch exchange and an operator terminal (10), is switched to a three-way call connection state, which is among the outside line (3), the operator terminal (10), and a supervisor terminal (20), using conference (52), in order to send advice or the like to an operator from a supervisor, a transmission line (31) of the outside line (3), a first transmission line (11) of the operator terminal (10), which is one of two transmission lines included in the operator terminal (10), a reception line (13) of the operator terminal (10), a transmission line (21) and a reception line (22) of the supervisor terminal (20) are connected to one of the conference trunks (52), which has been captured from among the available conference trunks, and a second transmission line (12) of the operator terminal (10), which is one of the two transmission lines of the operator terminal (10), is connected to a reception line (32) of the outside line (3). Then, the three-way call connection state is established. |
