Abstract: Methods of estimating if a voice signal is more likely formed by a machine or human, are disclosed. The methods are particularly well suited for use in an automated call establishment system. A voice signal is received at a computing device. Speech recognition steps are applied to the voice signal to recognize spoken words in the signal. Recognized words are compared to words likely generated by a machine or a live human. Based on the comparison, an estimate is made that the voice signal more likely originates with a machine or a human. Conventional call progress tone recognition may be combined with speech recognition to obtain an improved estimate of call progress. As a result of the methods, calls to machines may be disconnected or connected to a pre-recorded message, while calls to humans may be connected to call handling agents or a different pre-recorded messages. An automated call establishment system using the methods is also disclosed.