| 摘要 |
The invention relates to a method for a PBX system which is not isolated from the exchange system, i.e. which has no transformers, dialling memories nor conversion devices in the exchange system. In a system of this type, an enquiry call in the PBX system or suffix dialling in the exchange system is intended to be possible with simultaneous detection of noise pulses but without disturbing the distant exchange subscriber. This is achieved in that, in the case of an exchange connection and a first loop interruption, the loop relay detects an interruption, the exchange connection switches to "hold" and the extension switches to internal feed. If no further pulses occur, the switchover is reversed. If further pulses occur, these are used for internal dialling (enquiry call) or, if a first specific digit is dialled, through blocking of the switchover, for further dialling in the exchange. It can be used in small, low-cost PBX systems.
|
