Automatic telephony; a comprehensive treatise on automatic and semi-automatic systems (1921)
Smith, Arthur Bessey, b. 1875, Campbell, Wilson Lee · New York : McGraw-Hill · leaf 402
runk. Another method of handling dead-number trunk connections forparty lines, but one which is considerably more complicated and expen-sive, is to substitute for the telephone removed from any line a specialrelay connected to the line at the central office and designed to operateonly on ringing… … FIG. 2 B v * Z FIG. 1 C sy* tz Oper. set used + °— must hare cond. in line CCT. ~= D To Oper. % X£ All privates of dead lines conn. I to one trk. I.c.m. Mustbemultipled\ The Priv. nor. lineiSw.to be opened atthe Jack. 5.3 y ? A 1000 Fig. 297.—Trunk for connecting dead lines or numbers to an…
Telephone
Internet Archive · California Digital Library · Public Domain Mark 1.0. Free to use for anything.
![An illustration from [Electric engineering.] (1902)](https://img.insideoutlibrary.com/img/200/ia-electricengineer02inte-306-167.webp)
