GB397145A - Improvements in or relating to telegraphic installations - Google Patents

Abstract

397,145. Code telegraphy. SIEMENS & HALSKE AKT.-GES., Siemensstadt, Berlin. Feb. 17, 1932, No. 4721. Convention date, Feb. 17, 1931. Addition to 306,406, [Class 40 (iii), Telegraphs, Electric]. [Class 40 (iii).] A polarized slow-acting relay controlled by the line relay is used for holding the connection in a telegraph exchange during traffic. According to the parent Specification, an a.c. or other distinctive impulse is used for clearing, whereas d.c. impulses are used for automatic calling and for message traffic. According to Specification 314,974, [Class 40 (iii), Telegraphs, Electric], d.c. impulses are used for clearing as well as for message traffic ; the armature of the receiving relay at the exchange is moved by a d.c. calling impulse from the idle or "false normal" position (in which it shortcircuits the pre-selector) to the spacing position, the normal position during idle periods being the same as the marking position during traffic periods. According to the present invention, a slow-acting polarized relay T, separate from the line relay ER, is used at the exchange for this purpose. Fig. 1 shows a single-current line a b feeding a double-current line a<1> bl through a relay ER. When the armature er is in the full-line position (which is the rest position during idle periods and the marking position during a message) the current in winding I of relay T opposes that in winding II. When, however, the normally flowing current in line a b is interrupted, contact er moves to the dotted-line (spacing) position, and slowacting relay T pulls up, closing at t a circuit for operating the exchange mechanism. Thereafter contact t remains closed until the receipt of a marking signal of sufficient duration to release the slow-acting relay T. In the case where the incoming line a b works with doublecurrent and the outgoing line a<1> b<1> with single current, the relay T is connected in the former line, Fig. 2 (not shown). Fig. 3 shows the connections for a subscriber's jack at the exchange. A second subscriber together with exchange connections are represented by TA. A call from this latter subscriber completes a circuit through relay R, which pulls up and energizes winding I of relay ER via contact r. Armature er thereupon moves to the dotted position, and slow-acting relay T pulls up as described above. Through connection is thus established at t<1>, t<2>, and contact t<3> replaces contact r. Thereafter signals are sent on to the distant subscriber by contact er, and to subscriber TA by contact sr which has been set to the working normal (dotted) position by a return impulse sent by the distant subscriber to relay SR.