Method of automatic duplex or semi-duplex communication for two units via a telephone line

摘要

PCT No. PCT/FR93/01152 Sec. 371 Date Jun. 29, 1995 Sec. 102(e) Date Jun. 29, 1995 PCT Filed Nov. 23, 1993 PCT Pub. No. WO94/13094 PCT Pub. Date Jun. 9, 1994Apparatus and methods for establishing half-duplex communication between a first unit and a second unit over a telephone line. The first unit may transmit a first matching signal stream, the first matching signal stream including a first conditioning segment and a first unmodulated carrier signal having a first characteristic carrier frequency, the first characteristic carrier frequency representing a given transmission mode, the given transmission mode being in half-duplex. The second unit may analyze the first characteristic carrier frequency to recognize the given transmission mode.