Abstract: An audio-visual telecommunications system comprises a videophone terminal including a videophone communication interface for making a connection to a telecommunications network. A picture processing unit receives audio-visual signals from the videophone terminal which it process in order to compose a picture with sound. The picture processing unit transmits signals representing the composite picture to a television set. The picture processing unit includes an image memory which stores visual signals in a digital form as they are received from the videophone communication interface. A time base receives a composite video signal from the television set and extracts the line and frame synchronized signals. The time base controls a read-out which is synchronized with the extracted synchronization signals and formed responsive to the signals stored in the memory.