 |
 |
|
|
 |
|
|
|
|
|
|
The digital electronic switching system is almost the same as the analog electronic switching system in terms of the control subsystem. However, the speech path subsystem employs a new system without mechanical components, called a time-division speech path which enables direct switching of digital signals. A call is connected by changing the sequence of analog signals which are multiplexed in a binary coded pulse train and carried as digital signals. Using optical fibers, the digital electronic switching system can implement digital integration. NTT has been promoting development and introduction of more advanced and efficient communications systems such as ISDNs.
