Method for double-ended line qualification and monitoring of xDSL links

A method for double-ended line qualification and monitoring of xDSL links employs a single test program which is sent by a first subscriber at one end of the xDSL link to a second subscriber at the other end of the xDSL link. Line qualification and/or monitoring is carried out by processing this test program and sending the test results obtained in this step back to the first subscriber. The line qualification and/or monitoring is triggered after the code of the test program has been transmitted by the first subscriber. In this method, the first subscriber represents a modem at the switching end and the second subscriber represents a modem at the subscriber end. The test program is a program module which is connected to other program modules via a message queue.