| 摘要 |
PROBLEM TO BE SOLVED: To provide a communication controller capable of reducing the component cost because a dummy unit is not required, and the supervisory function can be centralized, capable of detecting unauthorized connection of an electronic apparatus with a communication system, and the communication system is less likely to fall into communication disabled state.SOLUTION: A communication controller 5 is connected with a network, through which a plurality of communication devices connected with a pair of communication lines of trunks 3b, 3c, perform communication, respectively, and mediates communication between the networks. The communication controller includes shortening circuits 22a-22c for shortening the rising or falling time of the communication signal waveform on the communication line, close to the limit of establishing communication, transmission sections 20a-20c transmitting a test signal for determining whether or not the communication is established in the network, at a predetermined time, and judgement sections 21a-21c for judging whether or not the communication is established when the transmission sections 20a-20c transmit the test signal in the network, and the shortening circuits 22a-22c are turned on.SELECTED DRAWING: Figure 2 |
