Circuit arrangement for a telephone -, in particular private branch exchange with the code choice and pulse selection of the public address systems

摘要

1,029,351. Automatic exchange systems. SIEMENS & HALSKE A.G. April 23, 1964 [April 26, 1963], No. 16788/64. Heading H4K. A PABX has some subscribers with impulse transmitters and others with code senders, both sets of subscribers having access to the same relay sets which distinguish between the types of substation gaining access. The substations are connected to the relay sets over a line finderfinal selector, the code sending substations being multipled to each relay set over one bank of the finder-selector so as to operate a code-sending relay in the relay set. The code sending relay is energized by discharge of a capacitor, connected up on seizure of the relay set, and connects up a decoder which governs an impulse generator repeating each code received as impulses to line. The impulse sending substations produce no switching in the relay set when this is seized, the relay set standing normally in a condition to repeat the received impulses to line. The impulse sending stations have an earth key actuation of which during a connection with the public exchange enables the substation to transfer the connection to another substation designated by dialling. The code sending substations obtain this facility by means of a particular code. The relay sets over which such transfer paths are set up may be of a kind to handle calls from both types of substation or may be of different sorts depending on the type of substation.