| 摘要 |
1,063,939. Automatic exchange systems. STANDARD TELEPHONES & CABLES Ltd. Nov. 10, 1965, No. 47657/65. Heading H4K. In an exchange employing a co-ordinate switching matrix SM, for example of reed relays, a calling line is connected over the matrix to an idle link circuit CC and thence to a register REG, and the required call is subsequently established by the connection of the same link circuit over the matrix to the wanted line, the register being released. The registers R1 . . . . R3 and subscribers' lines are scanned under the control of a distributer DT, and a generator SG supplies in code form the identity of the lines. In each line circuit a gate G2 picks off the code from highways OH, and this is transmitted in the case of a calling line over gate G3 and highway H1 to a common control circuit CCM, or in the case of a busy line over gate G4 and highway H2. Other common highways mark the line circuits according to their condition. When a calling condition is found, a gate G1 is inhibited to stop the scan, and over highway H3 and gate G5 the line circuit is marked busy. An idle register and link circuit are allotted, and a mark is applied to highways H4, H5, the latter serving to provide a correct termination in the case of 4-wire switching. In consequence, markings are applied to leads RML, MHL to establish a connection between the line circuit LC and the register REG via the link CC. Scanning now restarts. The dialled number is received in a VF receiver VFR, and is compared with the numbers emitted by the generator SG over highways OH. When agreement is reached, the register sends a signal over H6 to the control circuit CCM to stop the scan in the position of the wanted party. In addition, a signal over H7 operates a gate G9 in the link CC, and a signal over H8 from the control circuit CCM marks the identity of the called line circuit, in order to connect the link CC thereto over the switching matrix. Ringing takes place, the register is released and scanning is resumed. If the marking on the called line circuit indicates a busy condition, no connection is set up and busy tone is returned. |
