| 摘要 |
PURPOSE:To house an ISDN terminal and a dedicated telephone device via a common connection means by supplying power to the dedicated telephone device via one of first and second connection means and one of third and fourth connection means. CONSTITUTION:First to fourth transmission lines TA, TB, RA, and RB are wired to pins 1 to 4 of an MDF connector 15, the pins 1 to 4 are connected with a rosette 24 via four line cables, and a 100OMEGA terminating resistor 25 is provided between TA and TB as well as between RA and RB on the rosette, respectively. The rosette 24 is connected to an ISDN terminal 26 via the four cables. Since the pin 1 is connected to the TA, the pin 2 to the RA, the pin 3 to the RB and the pin 4 to the TB, the line between the pin 1 and the pin 2 to which a +24V voltage is applied is open, so the trouble of resistance breakage can be prevented. Thus, an adverse effect caused by excessive voltage applied to the ISDN terminal 26 can be eliminated. |
