| 摘要 |
a. Electronic circuit connectable to the line of a telephone subscriber, producing in the event of a call the closing of the loop, followed next by a return to the open state and in which the time between the said closing and the said opening is used to carry out one or more of the functions described below. b. The functions carried out during the time specified above are the sending to the caller of the surrounding noises from a microphone connected to the device, the transmitting by the caller of a message which will be recorded by an ad hoc element connected to the device, the transmitting to the caller of a message previously recorded in an ad hoc element connected to the device, and the counting of the number of calls. <IMAGE>
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