| 摘要 |
<p>PROBLEM TO BE SOLVED: To enable utilization by freely selecting the reliability of line by a user by providing a means for applying a specified act bit, means for applying a specified system select bit and means for identifying the cells of two systems. SOLUTION: Act bit application circuits 3-0 and 3-1 fetch the cells of two systems mutually indepndent while being provided at inputs and apply the act bit showing the active system to both the cells of two systems. Besides, header application parts 6-0 and 6-1 are provided with system select bits at cells and identify the cells of two systems for these system select bits. Further, system selecting filters from 5-5 to 5-8 are connected to respective (k) ports and according to this system select bit, the cells of two systems are identified. Thus, the user can utilize the line while freely selecting its reliability, the economical line adaptive to communication quality is utilized and even when the line is made into one-system two lines or two-system one line, it can be adaptively used.</p> |
