| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To avoid interference between ISDN and xDSL caused by difference in line length between an ISDN subscriber and a subscriber for receiving xDSL service, even if DSLAM is set outside a station office. <P>SOLUTION: An ONC14 and a 0.4 kHz extraction circuit 20 are provided in the same feeder point B as DSLAM34 which is a digital circuit terminal installed outside, in a subscriber telephony system equipped with ISDN and xDSL. The ONC14 is a subscriber line terminal dedicated for 0.4 kHz extraction that branches ISDN data from an ONU12 in the feeder point B. The 0.4 kHz extraction circuit 20 extracts 0.4 kHz clock of ISDN reference signal from the ISDN data supplied from the ONC. The DSLAM transmits xDSL data to a xDSL circuit 35 in synchronous with the 0.4 kHz clock from the 0.4 kHz extracting circuit. Since, with this system, the distance between the feeder point and an ISDN subscriber house C and the distance between the feeder point and an xDSL subscriber house D are short, the clock with small phase difference is supplied. <P>COPYRIGHT: (C)2005,JPO&NCIPI</p> |
