MODEM COMMUNICATION SYSTEM HAVING TRAINING MEANS AND METHOD FOR TRAINING SAME

摘要

ABSTRACT OF THE DISCLOSUREA multipoint type MODEM communication systemhaving a training device for adapting receivingparameters in a receiving MODEM to a characteristic of atelephone line connected to a sending MODEM in responseto a training signal sent from the sending MODEM priorto the reception of data. The training signal includesa tone used for gain control, a timing signal used forpull-in synchronization, and at least two impulses usedfor equalization and carrier-phase-control, which aresuperimposed on each other. A time between the firstand the last impulses defines the characteristic of thetelephone line which should be adjusted in the receivingMODEM. Additional guard impulses may be added prior toand/or after the impulses. A scramble signal also maybe added after the impulses. In addition, a method fortraining the receiving MODEM is disclosed.