| 摘要 |
<p>Different types of transmission are controlled by a standard procedure in a telephone exchange with a central digital controller. All the connections are continuously sampled in sequence and a character, indicating the line condition, is entered in a 'last look' store assigned to the connection. If the condition has changed since the previous sample, appropriate instructions are read out of a PPROM and executed by the controller. The advantage of the system is that only the PROM has to be modified if a new type of transmission is introduced.</p> |
