Circuit arrangement for selbsttaetige or for searching, selected league be prepared and holding of connecting routes

摘要

1,083,473. Automatic exchange systems. PHILIPS ELECTRONIC & ASSOCIATED INDUSTRIES Ltd. Nov. 15, 1965 [Nov. 18, 1964], No. 48315/65. Heading H4K. In a switching network comprising a number of relay-controlled matrix stages A, B, C an idle path being determined and subsequently held over the c-wire, each interstage link AB, BC is associated with a pair of transistors T 1 , T 2 connected as shown. In the case of a busy link, diode DTL is conductive and T 2 is saturated, so that T 1 cannot operate. A marker applies negative battery at m 1 to the network and, provided an idle path exists, SD responds. In consequence, switches SKAB, SKBC operate in succession to choose a single idle path. The corresponding relays Klm, Kpq, Krs energize and hold in series.