| 摘要 |
PROBLEM TO BE SOLVED: To provide a TCM-ISDN having a DSL channel to avoid a noise since a frequency band to be used for adding the DSL channel to the TCM-ISDN is as wide as about 320 kHz to become a noise factor for the DSL channel. SOLUTION: Two subscriber's lines of the ISDN to use the same assembled transmission line desiring the addition of the DSL channel are made to one set, the incoming signal and outgoing signal of the ISDN of each of subscribers are separated, and the ISDN signals of two subscribers are multiplexed so that two twist pair cables in the assembled transmission line prepared for two subscribers can respectively transmit only incoming and outgoing signals. Thus, the frequency band to be used can be lowered. Further, on the cable for transmitting the incoming of ISDN, the incoming DSL channel is multiplexed but on the cable for transmitting the outgoing of ISDN, the outgoing DSL channel is multiplexed and the DSL signals of two subscribers on both cables are transmitted to share the DSL channel while dividing the frequency.
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