| 摘要 |
PROBLEM TO BE SOLVED: To provide a communication device connection changeover device that is automatically switched depending on a signal transmission system of a telephone line and a line class by having only to be connected without the need for changeover depending on the signal transmission system and the line class of the telephone line used by the user. SOLUTION: In the communication device connection changeover device 30, after confirming a PB/DP signal detection section 36 detects a PB signal or a DP signals sent from a communication device 22, whether or not a dial tone signal detection section 37 detects a dial tone is discriminated. When no dial tone is detected, the PB signal or the DP signal which is detected is used to make signal transmission reception between a device connection terminal 31 and a common input terminal 32 and when the dial tone is detected, the PB signal or the DP signal which is not detected is used to make signal transmission reception between both the terminals 31, 32 by means of a control means 38.
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