| 摘要 |
PURPOSE:To effectively utilize a communication line by simultaneously discriminating two kinds of patterns in each mode by means of a control means. CONSTITUTION:A code conversion circuit 1 is set up to a prescribed code conversion mode and the generation pattern of a pattern generating circuit 2 is set up to a pattern inserted into an I channel. Data on the I channel side are compared with data generated from the circuit 2 and data to which polarity is inverted by an inversional circuit 9 by data comparators 61, 62. Error counters 31, 32 count up the number of noncoincident pulses, and when the counted value exceeds a set value, noncoincidence is decided by coincidence circuits 41, 42. When the circuits 41, 42 decide the noncoincidence, a pulse is generated from an AND circuit 11, a 1/2 frequency dividing circuit 10 is driven, an output from the circuit 10 is inputted to a selection signal switching circuit 8 and the mode of a conversion mode selecting circuit 5 is switched. When either one of the circuits 41, 42 decides coincidence and the other decides noncoincidence and when both the circuits 41, 42 decide coincidence, the mode of the circuit 5 is switched to discriminate a pattern. |
