. Automatic telephony; a comprehensive treatise on automatic and semi-automatic systems . up, relay RA6 will fall back andlight the lamp L-9. When the calling subscriber hangs up it causes therelease of the first selector. This allows relay ZM4 to fall back, whereuponthe circuit of the lamp L-10 is closed through main spring r-441, backcontact, to the front contact of relay R-45 main spring r-452, through thesleeve side of the trunk circuit to main spring r-442, through its backcontact, through the front contact of main spring r-453. Upon seeing AUTOMANUAL SYSTEM 275 both the lamps L-9 and L-1
. Automatic telephony; a comprehensive treatise on automatic and semi-automatic systems . up, relay RA6 will fall back andlight the lamp L-9. When the calling subscriber hangs up it causes therelease of the first selector. This allows relay ZM4 to fall back, whereuponthe circuit of the lamp L-10 is closed through main spring r-441, backcontact, to the front contact of relay R-45 main spring r-452, through thesleeve side of the trunk circuit to main spring r-442, through its backcontact, through the front contact of main spring r-453. Upon seeing AUTOMANUAL SYSTEM 275 both the lamps L-9 and L-10 lighted, the B operator will pull down theconnection, which will allow the cut-off relay .R-48 and the trunk relayjK-45 to fall back. If desired, the number of the called subscriber in the manual office canbe transmitted by impulses and set up before the B operator, who thenneeds only to read off the number and make the connection accordingly. A small installation of five hundred lines is shown in Fig. 234. Theoperators desk may be seen in the center foreground. It is equipped with. SECTION x-xFig. 239.—Side view of 2-motion switch. one key set, having three digits (rows of keys) and an additional row offive keys for party lines. A rotary switch, such as used for the distributor switches and the fre-quency selector, is shown in Fig. 235 and 236. The magnet has a knife-edge pivoted armature, retained by coiled springs, adjusted by screwsin the armature. The bank has 20 points. The line relay (Fig. 237) has a heel piece which makes two bends, oneend carrying the core and the other used for mounting. The armature ispivoted to the back end of the magnet, through a hole in the heel pieceIts finger projects forward to operate the springs. 270 A U TOM A TIC TELE IHON Y In the view of a switch unit (Fig. 238) the wiper shaft is at the rotary ratchet wheel is pinned to the shaft and rotates and rises withit. The rotary detent is in the form of a long plate which holds the w
Size: 1382px × 1808px
Photo credit: © Reading Room 2020 / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1900, bookdecade1920, booksubjecttelephone, bookyear19
