Three level subscriber signaling for data network. - Yasunori Nishizawa; Hidenao Munakata; Hiroshi Sunagawa; Hiromasa Ikeda (DATACOMM, 1973)

Three-Level Subscriber's Loop Signaling for a Data Network. - Hiromasa Ikeda; Yasunori Nishizawa; Hiroshi Sunagawa; Jiro Yamagata (IEEE Trans. Commun., 1976)