| 摘要 |
PURPOSE:To perform the transmission control of packets efficiently to prevent the collision of packets, by executing buffering of data, retransmission control, etc. on the level of interface and making the transmission of data packets impossible while a signal is generated from a collision preventing circuit. CONSTITUTION:The collision of data packets is caused when two or more terminals try to transmit data packets simultaneously in the common channel system. For the purpose of resolving this problem, the back-off processing for transmitting data packets again after a certain time from the detection of collision is performed. When collision is detected by a collision detecting circuit CO, the transmission of data packets is stopped, and a line is raised to the high level to facilitate the detection of collision. Next, the rise of a signal CD2 is detected, and a prescribed back-off timer value is read out from a random number table TBL of a memory 4 at the timing of the fall and is set to a timer T of a control circuit 6. After the set prescribed time elapses, a CPU5 detects the signal CD2, and the transmission operation is repeated if the access is possible. |
