| 摘要 |
PURPOSE:To reduce the time required for establishment of synchronism at the start of communication by blocking the transmission from a terminal device until the number of times of detection of synchronizing codes from an automatic exchange reaches a prescribed number of times. CONSTITUTION:A terminal device keeps solely the receiving state at the beginning of start of communication so as to detect a reception synchronizing code rc one by one bit while shifting the code. When a counter circuit 10 detects the code by a predetermined reference number (n), the circuit 10 outputs a count output (g) so as to make a gate 11 conductive. As a result, a transmission/reception switching signal (e) is changed over at each transmission reception period and a transmission synchronizing code sc is transmitted to a 2-wire circuit 1 at the beginning of transmission period. The automatic exchange establish the synchronism by receiving the transmission synchronism code sc transmitted from the terminal device. |
