| 摘要 |
PURPOSE:To easily detect a multiple access collision, by sending values inherent to each terminal after encoding to the access channel of an ascending transmission line and judging as an access collision when it is discriminated at a center device that the code comes off from the encoding side. CONSTITUTION:A center device 1 turns off the ''being accessed'' displaying channel B and collision displaying channel C of a descending line R when no access signal exists in the access channel A of an ascending line T. Upon detecting this, each terminal device 2-5 send access signals to the channel A by encoding Nos. allocated to each terminal. The receiving section of the center device 1 detects these signals and, when the device 1 judges that some of the codes come off from the encoding side, discriminates that a collision occurs due to simultaneous accesses from terminals of more than two and turns on the channels B and C. Upon detecting this, each terminal stops their accesses and restarts their accesses after a random time has passed. |
