| 摘要 |
PURPOSE:To use lines equally and efficiently and to reduce the irritation of subscribers by providing a function by which a subscriber code is stored in an exchange device if all lines are busy when connection is requested from a subscriber to the exchange device. CONSTITUTION:When the number (n) of lines is smaller than the number N of subscribers, subscribers C and D cannot use lines if subscribers use lines (a) and (b). If connection is requested from the subscriber C or D in this state, a busy tone is not answered back to the subscriber but its subscriber code is stored in a temporary memory. If connection is requested to the exchange device from subscribers A, B, C, and D in order when all lines are busy, subscriber codes are stored as shown in a figure 2. When one line becomes idle, the code of the subscriber A which is first held is taken out from the memory to connect the subscriber A to the line. Priority levels of remainder holding subscribers are raised by one, and the memory state is as shown in figure 3. |
