| 摘要 |
PURPOSE:To execute highly reliable communication with the use of a power supply line with a large amount of noises by detecting errors not only in units of but nut also in units of block. CONSTITUTION:In a transmission side unit, a parity bit is added to data to be transmitted by a transmission data generating means 10, and set to a data string constituting means 16, where data from the means 10 is inputted to the 1st and 2nd data buffers 36 and 38 and stored at every transfer block. The 1st communications input means 12 receives data from a power supply line 20 and FM-demodulates it, and the demodulated output is transmitted to a NAK/ACK signal detecting means 14. The means 16 transmits the data string constituted by adding a check sum to data at every block from the buffers 36 and 38 with the aid of the detecting signal from the means 14 to the power supply line 20 through the 1st communications output means 18. The receiving side removes the check sum from the input data, checks the parity of the data, compares the extracted check sum with a calculated value and transmits an ACK signal and an NAK signal to the transmitting side when no error is obtained and when it is obtained, respectively. |
