This invention relates in general to data communication, and more particularly to a loop integrity test device and method for digital subscriber line (xDSL) communication.
Digital subscriber line (xDSL) communication can provide a high bandwidth data path supported by the twisted pair wiring infrastructure of the public switched telephone network (PSTN). xDSL technologies support data service simultaneously with traditional telephone service using a separation technique. Suitable xDSL technologies include asymmetric digital subscriber line (ADSL), rate adaptable digital subscriber line (RADSL), symmetric digital subscriber line (SDSL), high-speed digital subscriber line (HDSL) and very high-speed digital subscriber line (VDSL).
In general, an xDSL communication link is established across the local loop between customer premises equipment (CPE) and the local loop termination point (e.g., central office or remote terminal). The local loop termination point typically has a xDSL access multiplexer (DSLAM) that handles the xDSL link on the network side, and the CPE typically includes one or more xDSL termination units (XTU) that handle the xDSL link on the customer premises side. One architecture for xDSL communication is disclosed in U.S. Pat. No. 5,668,857 Sep. 16, 1997, and entitled xe2x80x9cCommunication Server Apparatus and Method.xe2x80x9d
In order to support xDSL communication, the twisted pair line on the local loop between the customer premises and the loop termination point must meet certain physical characteristics. If it does not, an xDSL communication link can not be successfully established. Consequently, it can be desirable to allow the xDSL capability of the local loop to be quickly verified at the same time that xDSL service is installed at the customer premises. Further, it can be desirable to monitor the xDSL capability of the local loop on an ongoing and continuous basis.
In accordance with the present invention, a loop integrity test device and method for digital subscriber line communication are disclosed that provide advantages over conventional xDSL communication devices and systems.
According to one aspect of the present invention, a digital subscriber line (xDSL) communication system allows xDSL communication across a local loop. The system includes a local loop termination point and customer premises equipment connected to a twisted pair telephone line. Loop integrity test devices for xDSL communication are located at the local loop termination point and the customer premises equipment and are coupled to the telephone line. The loop integrity test devices are respectively operable to transmit test signatures across the telephone line, to receive and evaluate test signatures from the telephone line, and to indicate whether the telephone line can support xDSL communication based upon evaluation of test signatures.
According to another aspect of the present invention, a loop integrity test device is disclosed that includes a line interface unit operable to connect to and interface with a twisted pair telephone line. The test device also includes an output device operable to indicate a pass state and a fail state. Further, the test device includes a control unit having a generation unit and an evaluation unit. The generation unit is operable to transmit a test signature across the telephone line. The evaluation unit is operable to receive and evaluate a test signature to determine whether the telephone line can support xDSL communication. The control unit is then operable to direct the output device to indicate a pass state if the telephone line can support DSL communication and to indicate a fail state if the telephone line can not support xDSL communication.
A technical advantage of the present invention is that the integrity of the local loop can be verified at the time of installation of high speed xDSL data service at a customer premises. In particular, the present loop integrity test device provides an immediate indication of whether the loop can support xDSL communication when it is installed.
Another technical advantage of the present invention is an improvement in the reliability and monitoring of the xDSL communication system. The test devices implement a continuous integrity check of the local loop that allows the telephone company or other service provider to be alerted to a problem on the local loop. This notification may allow the service provider to correct the problem before a degradation of service is noticed by the customer.
Other technical advantages should be readily apparent to one skilled in the art from the following figures, description, and claims.