| 摘要 |
In the connection of a number of telephone sets (1) to a private branch exchange (3) control information is communicated between the telephone sets and the exchange set in such a way that a bidirected conversion unit (19) is required. In order to provide a high degree of service at a reasonable cost the telephone sets (3) are collected in groups which share a generally small number of conversion units. By means of suitable control means (17) and switch units (15, 21) in the forwarding of control information, a suitable non-occupied conversion unit (19) can be selected. <IMAGE> |
