| 摘要 |
PURPOSE:To realize an efficient office outgoing-incoming call connection of an office trunk by making an advance of the route of an office outgoing call in an overflow state under the control of an attendant board. CONSTITUTION:Common controller M is provided with a circuit which exercises a supervision over the busy state of an office trunk, and attendant board ATT with a key which controls a route advance, so that when the number of busy office trunks exceeds a fixed number, a route advance of an office outgoing call from an extension subscriber will be made to attendant board operator's call connection (2). On judging that an attendant board operator is in an emergency, a connection between extension subscriber SUB and attendant board operator's call trunk ORT is made and a call is enabled via route (3). |
