| 摘要 |
<p>The synchronous data transmission system reduces the chance of losing synchronisation but it is able to operate without continuously exchanging data. When a signal is ready for transmission at the wrong time, a continuous signal is transmitted turning on the signal and block counters. At the receiver this continuous signal is detected as noise. After the apparatus has switched over to the reserve control (ZST-E) from the main control (ZST) the reserve control causes synchronising and return signals to be sent immediately. Synchronisation of signals is achieved with minimum expense and minimum transmission of special signals.</p> |
