| 摘要 |
1,156,886. Automatic exchange systems. INTERNATIONAL STANDARD ELECTRIC CORP. 5 May, 1967 [11 May, 1966], No. 20926/67. Heading H4K. In an automatic exchange with a central control servicing a plurality of calls in time divided manner and having a common store with a different section allotted for each call and functioning as a register for all data relating to that call, each register section includes a location in which is recorded an indication of whether the call is a local or trunk call and a further location which receives the number of a called subscriber in the case of a local call and functions as a buffer store for dial pulses to be sent to the remote exchange in the case of a trunk call. As shown, for local calls subscribers such as TlnA and TlnB are connected to opposite sides of local junctors VSi through a switching network KN in known manner while for a trunk call a local subscriber is connected to an outgoing junctor VSa. The subscriber circuits and junctors are scanned cyclically by a scanning device A. The central logic L constantly receives the switching conditions of the elements being scanned. The central logic assigns for each connection to be established a storage section formed by a row R1 . . . RN of a core store MR. A portion RT of that row is used to store the number of the calling subscriber as derived from the position of the scanner. A portion GT receives the number of the wanted subscriber. If the central logic determines after having received part of the wanted number that an outgoing line is required an indication of this is stored at a location K in the corresponding storage section. As dial pulses of the next digit are received they are accumulated in a location Z1 After the first such pulse has been received a gate T is opened gating pulses from a central pulse generator IG to the outgoing junctor and thus to the outgoing line. These pulses are simultaneously fed to the central logic and are accumulated in a location Z2. The number stored at the location Z2 is normally one less than the number stored at Z1. During an interdigit pause these numbers become equal. The central logic responds to this by closing gate T and clearing the locations Z1 and Z2 ready for the next digit. If required for subsequent switching the initial digits used to determine that a call is a trunk call may also be stored at GT and transmitted to the remote exchange. |
