| 摘要 |
PROBLEM TO BE SOLVED: To provide a communication system, that conducts communication independently of whether an exchange station has a no-ringing function. SOLUTION: A terminal use network control unit T-NCU7 has a call reception function for a no-ringing call receiving system and a selective ringing call reception system, utilizes the no-ringing call reception system under an environment where the no-ringing call reception system is available, and utilizes the selective ringing call reception system under the environment, where the no-ringing call reception system is not available. There are three switching ways of call reception system as a method (401) that selects the call reception system by using a text from a center 3 in advance, a method (402) that awaits the signal by both the call receiving system at all times and a method (403) that switches the call receiving method, by using a text from a changeover switch 8 or a meter 9 (or setting device 13) of the T-NCU7.
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