| 摘要 |
<p>D.M. Davidson - J.R. Bungard R.A. Gatward 5-2-2 TELEPHONE EXCHANGE An automatic telephone exchange, such as a PABX, includes a number of group control units (GCU1 to GCU4) each of which is a simplified version of the system of U.S. Patent No. 4581733. These are connected via respective PCM highways to a central switch, which is an electronic time space switch, and a central controller. The central controller does the major part of the call setting and control, all calls being set up via the central switch.</p> |
