| 摘要 |
PROBLEM TO BE SOLVED: To eliminate the noise of signal on an ADSL line and limitation in transmission distance caused by attenuation by locating an ADSL station device out side a station, when an ISDN and the ADSL of an Annex C system are used concurrently. SOLUTION: In a system for exchanging digital signals, by using concurrently an xDSL line between a station 1 which uses both the ISDN and the xDSL and a subscriber's home 2, an xDSL station device (A) is installed outside the station and a data line for digital signal transmission and a clock signal transmission line which serves as the reference of ISDN signals are provided between the xDSL station device and the station. |
