Patent ID: 7369516

Claim:
A method for transmitting data signals on a modem connection between a first and a second modem, comprising: determining echo cancellation coefficients for the first modem; transmitting data signals in full duplex between the first and second modems; providing a transmission hiatus of the second modem, in which an average energy of signals on a transmission line of the second modem is lower than in full duplex transmission; identifying the transmission hiatus of the second modem by the first modem, by determining that the energy of the signals received by the first modem from the second modem is below a predetermined threshold energy; beginning updating echo cancellation coefficients of the first modem, responsive to identifying the transmission hiatus of the second modem; identifying further transmission hiatuses of the second modem by the first modem, by counting sampling periods, which sampling periods are a reciprocal of the sampling rate at which data signals are generated for transmission; and periodically repeating the identifying of the transmission hiatus of the second modem by the first modem in order to recalibrate timing of the first modem, wherein providing the transmission hiatus comprises decreasing the number of symbols in a transmission window, from which signals are provided to the transmission line.