摘要 |
PURPOSE:To decrease the number of signal lines with no deterioration of both transmitting speed and efficiency of data and to reduce the overall production cost of a data transmission system, by inserting a status signal between transmission data. CONSTITUTION:A status signal (c) which shows the system state of a transmission line, each station, etc. in the form of H and L levels is supplied to an AND gate 41 from a CPU31. The output of the gate 41 is supplied to a synchronizing circuit 38 and an encoder 36. The encoder 36 synchronizes an input NRZ signal with a clock signal, and converts the result into a B.F signal to transmit it to an optical transmission module 43. While the B.F signal sent from a photodetecting module 46 is supplied to a decoder 37 and a ''1'' counter circuit 47. An FF48 is set by the output obtained when the circuit 47 counts ''1'' >=7 times, then reset by the output obtained when the circuit 47 counts ''1'' <=6 times. The output Q of the FF48 is supplied to the CPU31 in the form of a status signal. |