| 摘要 |
PURPOSE:To execute the change of an encoding key, line, etc. optionally, to ensure secret security and omit an encoder prepared in each line, by providing encoding and decoding circuits in a communication control processor and controlling these circuits by a control program. CONSTITUTION:The communication control processor 3 is provided with a communication line scanning means CS, which consists of the encoding circuit 9, the decoding circuit 10, a line controlling part 6, an encoding controlling part 11, and a line selecting RAM13. The circuits 9, 10 are initialized by commands OUT A1-A4. The circuit 9 inputs key data OUT A1, A2 to determine the status of data conversion and outputs a key data A4 to the circuit 10 to enable the data A4 to be decoded. Subsequently, the RAM13 is initialized by A0. The contents stored in the RAM13 are read out by regarding the contents of a register 12 as the address and supplied as enable signals of the circuits 9, 10. The encoding and decoding are performed only when the output RD of the RAM13 to the line is ''1'' and the OUT A5 and IN A5 have been executed. Transmission is performed by a line controlling part 6. |
