if it is a bug or a feature when articles from the acm archive are open and free: this time, a real nice one - at least for me: "a digital communication network for computers giving rapid response at remote terminals", written 1967 by the npl people d.w. davies, k. a. bartlett, r.a. scantlebury and p.t. wilkinson | acm

electrical communication, 1960 have to read more of j.w. halina, and his ideas on data transmission, 1963.