A method and apparatus are provided for use in tracing transmission lines from a first location to a second location. The apparatus comprises a multi-channel speech synthesizer, a digital to analog convertor and a demultiplexer. The digital synthesized speech which can take any form is applied to a digital to analog convertor where it is transformed into an analog stream of distinct speech segments. In accordance with the corresponding method, the distinct speech segments are selectively connected by the multiplexer to one or more of the transmission lines to be traced. At the second location, the distinct speech segments are detected. As each distinct speech segment is associated with a particular transmission line, it is possible to distinguish between the many transmission lines which are being simultaneously traced.