The address generating device is provided for a communication line scanning device. The lines are connected to the scanning device through n line interface circuits, n varying in accordance with the network configuration. Each interface circuit can be connected to a various number of lines, for instance one line or k lines in a preferred embodiment, and comprises means for providing to the address generating device, a presence indicating signal indicating that it is plugged and a signal indicating the number of the lines connected thereto. A first logic circuit receives the presence indicating signals as inputs and generates on its outputs the address bits of the last present interface circuit to be scanned. A first counter able to count in binary mode up to n-1 is incremented by an increment pulse provided by a clock on each period assigned to the scanning of a line. This counter outputs the address bits of the successive interface circuits. A comparator compares the address bits so generated and the address bits of the last present interface circuit to be scanned and outputs a reset signal when these bits are equal.