Fuente: Wipo "digitalization" 799,481. Automatic exchange systems. GENERAL DYNAMICS CORPORATION. Sept. 24, 1956, [Sept. 26, 1955 ; Sept. 26, 1955], No. 29158/56. Class 40 (4). The system comprises party lines of different types in which the designations of the stations on the different types of line are arranged in different modes. When a party makes a call identifying means are conditioned, according to the type of party line, to operate in the appropriate manner to identify the calling party. The invention is described with reference to the Hudson office and a remote Russell office, both of which may comprise a number of exchanges. Each exchange has one or more trunk recorders for storing information concerning toll calls handled by its associated trunk circuit. Common recording equipment is provided, however, only in the Hudson office and is operated by playing back the information stored in the trunk recorders of both offices to produce printed or perforated tickets in respect of each toll call. Playback from the trunk recorders in the Russell office is transmitted to the common recorder in the Hudson office over v.f. channels. General operation of system, Figs. 1 and 2. Local calls are connected in known manner and are not ticketed. To make a toll call to a subscriber connected to an exchange in the Cleveland area, the calling subscriber dials an access digit indicative of the Cleveland area, selector 142 responding to this digit to seize a trunk circuit 126 extending to the Cleveland area. The subscriber next dials a party digit, which is the first entry made in the associated trunk recorder 127 and is not used for extending the connection. The trunk recorder is of the type described in Specification 757,125 and comprises an endless loop of magnetic tape having mark and space transducing heads adjacent lateral spaced areas of the tape. The party digit is recorded on the tape as a number of mark pulses followed by a space pulse. If the calling subscriber is on a private line this digit is arbitrary and has no significance. If, on the other hand, the calling subscriber is on a party line, this digit is his own party digit and is used in the determination of the directory number of the calling substation. The party digit operates a stepping switch in the trunk circuit 126 to energize one or more dialled party digit register relays. The calling subscriber next dials the code digits of the wanted exchange followed by the numerical digits of the wanted subscriber. These digits are recorded in the trunk recorder 127 in the form of groups of mark pulses separated by space pulses as shown in Fig. 120A. The stepping switch in the trunk circuit 126 counts the number of digits dialled and prevents recording of any digits dialled in excess of seven. Recording starting time. If the called line is busy, tone is returned and the connection released. If the called line is idle and is seized a supervisory relay in trunk circuit 126 pulls up to start rotation of a timer cam to restore the stepping switch and then advance it at the rate of one step per second. After a grace period of 8 seconds during which the calling subscriber may release the connection without change, a further supervisory relay operates to associate the trunk circuit 126 and trunk recorder 127 with a clock and calendar circuit 133 which transmits the date and time to the recorder. Identification of calling substation. The trunk circuit then grounds a common allotter start lead extending to an identifier sender allotter circuit 129 which associates an idle identifier sender such as 131 with the trunk circuit and with an identifier circuit 130. The allotter 129 also energizes an identification relay in the trunk circuit to apply an identification tone over an HS lead to a terminal or lead individual to the calling line circuit and selectively interconnected with an identification matrix 128 in accordance with the directory number of the calling substation. The indentification matrix comprises a termin