| 摘要 |
PURPOSE:To discriminate the reasons against improper connection of lines at a called terminal device by superimposing a message of the reasons of improper connection on a signal of improper connection, in a connection system using a signaling frame. CONSTITUTION:Frame information from a transmission line 1 is received at a frame reception circuit 2, a clear pulse from a frame synchronism circuit 3 is transmitted to a bit counter circuit 4 and a timing signal is applied to circuits 5, 9, 10 respectively. Further, the checking of the terminal is performed at a status discrimination circuit 12 via a channel 15 to inform to a control circuit 11. When it is discriminated as impossible communication, it is informed to an impossible reason superimposing circuit 10. This circuit 10 superimposes a message of the reason of improper connection of a line on a signaling frame, a frame multiplex circuit 8 superimposes a signaling packet to transmit it to a transmission line 14. Further, a calling terminal station device receiving the signaling packet discriminates the reasons of impossible connection at the discriminating circuit 7 for a reason of improper connection to inform it to the control circuit 11. |
