There is provided a method of detecting an infinite echo return loss (ERL) in an echo cancellation system while in a finite ERL mode. The method comprises determining a running mean attenuation by the echo cancellation system, determining a ratio of an echo signal to a near-end noise ratio (ENR), defining an infinite ERL threshold (TH.sub.infinite) as a function of the ENR, and switching to an infinite ERL mode as a function of the running mean attenuation and the TH.sub.infinite. The running mean attenuation can be enhanced echo return loss (ERLE), and the higher the ENR the higher the TH.sub.infinite and the lower the ENR the lower the TH.sub.infinite. The switching can further be a function of an energy distribution, where the switching switches to the infinite ERL mode based on a non-localized energy distribution over an echo path delay for a predetermined period of time.