Importance

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Abstract

A subscriber circuit is capable of realizing a CLIP service in an old-fashioned switching system. The subscriber circuit has a ringer transmitting circuit, which is connected to line A and line B, and which transmits a ringer signal in accordance with a ringer transmission request signal from a host system; a battery feed circuit, which supplies speech current to line A and line B; and a timer, which detects, in accordance with a change in the level of a ringer transmission request signal from the above-mentioned host system, the end of transmission of a ringer signal transmitted by the ringer transmitting circuit, starts timer operation, and ends this timer operation after a predetermined time has elapsed. The battery feed circuit supplies speech current to line A and line B from the above-mentioned battery feed circuit during the operation period of the timer.

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First Claim