| 摘要 |
PROBLEM TO BE SOLVED: To provide ISDN terminal equipment with built-in DSU, whose configu ration is simple and in which an incoming signal in an intra-device terminal can be monitored. SOLUTION: A down signal from DSU 2 to the intra-device terminal 3 is directly inputted to the intra-device terminal 3 through a line C by TTL connection. The incoming signal from the intra-device terminal 3 to DSU 2 is directly inputted to DSU 2 through a line B by TTL connection and it is outputted to an S/T connection point through a driver 13 and an S/T point transformer for intra-device terminal 4. The signal outputted to an S/T connection point is inputted to DSU 2 through an S/T point transformer 6, is outputted from the up signal terminals TA and TB of the S/T connection point and can be monitored from the outside. The driver 13 can be turned on/off by a switch 14 and it is turned off when it is not necessary to be monitored. Thus, power consumption is reduced.
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