Transforming four-wire to two-wire signals for data communication via telephone network, specifies numbers of amplitude levels which can be resolved

摘要

Amplitudes (P1, ..., Pn) of the signal (DS) on the four-wire transmission line are converted using a transformation (T). This transformation is so specified that the number (n) of different amplitude values (A1, ..., An) in the analog signal (AS), which can be resolved by the communication equipment, fulfills a given criterion (K). An independent claim is included for: corresponding equipment, equipment to detect a modem connection from a signal, a codec unit and a subscriber connection unit.