A system for permitting compatible communications among broadband and narrowband picture telephone installations, the bandwidth of a narrowband installation corresponding to the lower portion of the bandwidth of a broadband installation, in which the pictures associated with both types of installations have the same number of lines, the same line scanning frequency and the same frame rate, both the scanning of the subject image and playback are effected with a wave-shaped line scan for playback in a broadband installation, the signals in the transmitting portion of a broadband installation are split into a low frequency component, covering a bandwidth corresponding to that of a narrowband installation, and a high frequency component, and both components transmitted from a broadband installation are recombined in the receiving portion of a further broadband installation receiving the transmitted signals.