| 摘要 |
A telephone ringback apparatus includes a microprocessor-controlled communications device which is connectable with telephone equipment contained in a central office, such as a toll trunk facility, having the capability of identifying the number of a calling party. In response to the telephone user dialing a prescribed ringback access code, the apparatus signals the toll trunk facility causing it to transmit a message representative of the number of the telephone from which the user is calling. Upon receipt of this message the telephone number of the calling party is stored. A synthesized voice message is transmitted to the user instructing the user to hang-up. When the apparatus detects that the phone has been placed back on-hook, it proceeds to transmit dialing signals containing the previously stored number of the telephone, causing the calling party's telephone to ring. As an additional feature the apparatus is designed to carry out prescribed signalling tests, in response to prescribed test codes input by a craftsperson. Depending on the contents of a test code the apparatus may generate a series of prescribed tones or terminate the line with a precision impedance, enabling the craftsperson to conduct line quality measurements from his calling location.
|
