| 摘要 |
PURPOSE:To increase the sure functions, by changing the callout signal level at an extension callout device in response to the environment of installation. CONSTITUTION:Since an extension telephone set A is a telephone set installed in factories and requires a high voltage signal, when the telephone set A is called, a common controller CC catches a callout trunk RGT-H possible for high-voltage signal transmission and a network NW1. On the other hand, an extension telephone set B is a telephone set for offices and requires callout with a low-voltage signal. When the telephone set B is called out, the common controller CC catches a callout trunk RGT-L possible for low-voltage signal transmission and connects a network NW2. Thus, when the group of incoming extension telephone set is identified with the common controller, the callout trunk corresponding to the extension group is caught to change the callout signal level. |
