| 摘要 |
PURPOSE:To build up a private branch of mobile telephone exchange system covering the entire premises by providing a mobile telephone exchange function as one of functions of private branch exchange system. CONSTITUTION:Each of line circuits 51-5N is provided with a call signal transmission circuit 11, a DC supply circuit 12, a DC loop monitor circuit 13, a radio transmission reception circuit 14, a control circuit 15, a transformer 16, a mobile telephone set control changeover device 17, a radio frequency conversion circuit 18 and an A/D converter circuit 19. when mobile telephone sets 11, 12 are in use, the mobile telephone set control changeover device 17 of the line circuit connects the transformer 16 to the radio frequency conversion circuit 18. The control mechanism for accommodating a mobile radio telephone set is provided to the line circuits 51-5N of the private branch exchange system in this way, then a private branch of telephone line and a telephone set joint box being terminal equipments of the private branch exchange system are used as an antenna without any modification. |
