| 摘要 |
<p>The relay for switching into a subscriber circuit of a telephone exchange has a winding in its housing which consists of two coils wound in opposite directions, which are arranged in the subscriber circuit symmetrically with respect to the cradle changeover switch. Since the two coils complement one another in their field strength, it is adequate for each coil to be provided with a resistance of 5 ohms, and still to achieve reliable switching of the contact with a minimum possible loop current of 17 milliamperes. Such a relay in the subscriber circuit can thus also be used for new types of network systems with the abbreviated designation ISDN, as loop monitoring devices, in conjunction with new types of apparatus connecting cords of increased resistance. <IMAGE></p> |
