The invention refers to single-ended test of a loop (2, 3). A test device (TD1) is connected to a remote device (3) via a line (2). The remote device is powered on and transmits intermittently handshake signals (HS1), which can disturb the loop test. A receiving and calculating unit (RE1) detects the handshake signals (HS1) and orders a sending unit (SD1) to send a halting signal (NAK-EF) to the remote device. The latter is halted for predetermined silent period of time, during which the test or a part of it is performed. If required the halting of the handshake signals is repeated. The test device sends a broadband loop test signal (S1) and receives a reflected signal (S2) during the silent period. A frequency dependent echo transfer function is generated from the signals (S1, S2) and is used for generating desired properties of the line (2) such as its length (L).