| 摘要 |
A method of resynchronizing data transfer between two modems connected by a dedicated line following a fault caused by a ringing signal, whereby at least one of the modems is assigned to a central office and the other modem is assigned to a remote subscriber, is implemented by setting a ringing ID in the central office modem as soon as a ringing signal is to be sent to the subscriber modem connected via the dedicated line, transferring a ringing alert to the connected subscriber modem, interrupting transmission of the pilot tone accompanying the data transfer set by the central office modem and interrupting clock frequency synchronization implemented during data transfer in the subscriber modem with the pilot tone as reference, signalling the central office modem and subscriber modem on hold to save the characteristic parameters for the momentary data transfer in the two modems followed by transfer of the ringing signal via the dedicated line to the subscriber modem, resetting the ringing ID in the central office modem, resending the pilot tone via the central office modem and reinstating synchronization of the clock frequency in making use of the pilot tone as reference, restablishing the data transfer mode existing prior to step data) in making use of the characteristic parameters as saved before and synchronizing the subscriber modem to the data stream coming from the central office modem by searching for and detecting specific code groups ocurring regularly in the transferred data stream.
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