This shows the Grandstream Analogue Terminal Adapters that allow the old phones to connect to the digital system that supports the asterisk software. There are several spares and duplicates in this image. Also shown bottom R is the telephone tap that captures the audio from the telephone receiver and passes it through to the sound distribution system. (This is a compromise solution as I was unable to figure out how to do this using Asterisk.) Also shown is a Dialgizmo pulse to tone converter