| 摘要 |
PURPOSE:To facilitate the production of a modified code by utilizing an out-of- range data generated from an interface circuit characteristic of a modulator- demodulator so as to generate the modification code. CONSTITUTION:Sampling is applied a prescribed time after the final stop bit of a reception data group b' is detected and a data by one byte is fetched in a modification byte production collation circuit 24 as an out-of-range data (d). The data (d) is extracted from an out-of-range data group generated from the interface circuit characteristic of the modulator-demodulator 1. Then a modification byte (c) confirmed by the collation circuit 24 is stored in a modulo register of a cryptographic coding circuit 23 and the cryptographic coding is applied to a transmission parallel data (b) by using the modification byte (c). The cryptographic data is moved to a serial-parallel/parallel-serial conversion circuit 22 as a cryptographic transmission parallel data b', and sent to the opposite side as a transmission data group (a).
|
