Staas & Halsey
Signal sending control system
 A signal sending control system for use in a telephone system includes a ringing signal sending circuit having a signal source for generating a continuous ringing signal, interrupting means for controlling the sending of the ringing signal over each subscriber line, one switch for each subscriber line for selectively and switchably connecting the respective subscriber line to a speech network of the system and to the ringing signal sending circuit, a common controller for providing control information as to the duration of the ringing signal, and a control circuit for individually controlling the switching circuit of each subscriber line in accordance with the control information and for controlling the transmission duration of the ringing signal. 
Fujitsu Limited
H
H04M
inventional
Nobuyuki Yasuo Shoji Kenichi Hisao
Yasoshima Satake Nojiri Ogawa Kanzaki