| 摘要 |
1282541 Automatic exchange equipment PLESSEY CO Ltd 29 Dec 1970 [12 Jan 1970] 1346/70 Heading H4K A cross-bar switch has the self-latching springsets at the cross-points operated by the respective bridge and select magnets with the latter releasing after the connection is made so that the connection is held by the bridge magnet. Additional row and column conductors are provided and are interconnected by the springset at the operated cross-point to enable the select magnet circuit so that it can be re-operated to close a further cross-point in the same row when the respective bridge magnet is operated. In the switch shown, the switch cross-points are 11, 12, 21, 22 and the re-operate cross-point contacts are r11r, r12r, r21r, r22r which make connection to relays RM1 or RM2 thus closing a respective contact so that the respective select magnet SM1, SM2 can be operated again. As shown, bridge magnet BM2 and select magnet SM2 have been operated to close cross-point 22 and select magnet SM2 has been released by contact OS2 opening. Contact OS2 is inhibited from closing again by an engaged test circuit (not shown). In some circumstances it is required to transfer the output connection 02 from input I2 to input I1 which necessitates operation of bridge magnet BM1 and reoperation of select magnet SM2. Such circumstance occurs in a telephone exchange when a subscriber on 02 has to be transferred from a register on I2 to a junction supervisory set on I1 without breaking the subscriber loop. Select magnet SM2 can be re-operated to operate cross-point 21 since relay RM2 is operated through the re-operate contacts r22r, bc2 of cross-point 22. Crosspoint 22 is released by de-energizing bridge magnet BM2. A similar arrangement is described for a cross-bar switch having auxiliary and main rows of conductors, Fig. 4, 5 (not shown). In this case a diode is inserted in the connections to the re-operate column conductor to ensure that the system responds only to a re-operate signal. |
