| 摘要 |
PROBLEM TO BE SOLVED: To provide an off-talk communication service system that increases the number of information service channels and facilitates channel switching to overcome defects of a conventional off-talk communication service where the number of selected channels is limited to 4, the number of connectable center device is limited, and a changeover button has had to be depressed as many time as the number of switched channels at channel switching. SOLUTION: A subscriber exchange, that connects with an information service center by receiving a service start signal, a channel selection signal and an end signal by a high resistance loop signal sent from an off-talk communication service contract subscriber, is provided with a PB signal receiver having mis- reception prevention circuit to allow a channel switch of an in-station exchange to connect the contract subscriber and the information center. Thus, even when the number of the information centers is increased, the connection is facilitated and a channel number itself can easily be selected for the channel switching.
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