| 摘要 |
An intermediary plug has a plug unit on one side for connection to a telephone network. On the other side is an outlet for a telephone plug. If the male side of the intermediary plug is inserted into a connected telephone jack, two of its pins are connected to a station or exchange, and the other two are connected to a possible successive jack. Switches on the female side are closed if no plug is inserted in them.S The relay has three changeover devices. An operating voltage is connected between two poles, and can be 12 volts. If a transformer is connected after the coupling clock used, a normal coupling clock for heavy current can be used. The cut-off device is not connected to the telephone network if it lacks operating current. The device incorporates a resistance of 33 ohms, a capacitor with a capacitance dependent upon the properties of the relay, and can use the same voltage source as the relay. The changeover switch used is two-pole. (Provisional basic advised week 88/22) |
