| 摘要 |
<p>A telecommunications network includes local switches (14, 15, 16), main switches (10 to 13) and local access lines (20, 21). A switching which takes the form of a computer with switching capability is connected to the local switch (16) on a 30 channel ISDN link. In order to provide a private circuit between a local access line (20) and a local access line (21), each of these local access lines is connected at the customer's end to an automatic answering device, for example, answering device (27 or 29), which is connected to a telephone instrument, for example, telephone instrument (28) or telephone instrument (30). The following operations are then performed by a user who may be a customer or a network operator. The user calls the switching unit (25) from a telephone instrument connected to any one of the local access lines. The user then enters a user identifier and, using the keypad on the telephone instrument, instructs the switching unit to form a private circuit between the two local access lines. The switching unit (25) then calls each of the two local access lines. At the customer end of each of the local access lines, the call is automatically answered using the automatic answering device. The switching unit (25) then forms a private circuit by connecting the two local access lines together within itself.</p> |
