| 摘要 |
The invention relates to an electronic device capable of momentarily keeping an established telephone connection, without any instrument connected to the same line is kept off the hook. The device comprises a voice frequency decoder which activates a time-delayed relay for telephone line acquisition when it recognises the code sent by the star key or the crosshatch key of an ordinary telephone instrument. One single device allows several telephone instruments to take advantage of the momentary preservation of the established line. <IMAGE>
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