Method and device for detecting an off-hook condition of a local telephone and modem including such a device

摘要

The invention relates to a digital device for detecting the hold by an apparatus (8) of a telephone line (5) into which is plugged a modem (4) employing band superposition transmission, the modem (4) sending a send signal (IN1) on the telephone line (5) and receiving from this line a digitized reception signal (OUT2), characterized in that the said device comprises: a means (13) for providing a parameter of the transfer function (K) of the send signal (IN1) on the reception signal (OUT2), the said parameter being characteristic of the presence of at least the said apparatus (8) on the line (5), control means (17) for controlling the interruption of the exchanges of signals of the modem on the line (5), the said control being dependent on the said parameter of the transfer function (K). The invention also relates to the method implemented by the device of the invention, a modem comprising this device and a server of an Internet access provider using such a modem. <IMAGE>