Definition: V.17

An ITU fax standard (1991) that used trellis-coded modulation (TCM) at 12,000 and 14,400 bps for Group 3. V.17 also added TCM to the V.29 standard at 7,200 and 9,600 bps to allow transmission over noisy lines. V.17 defined special functions (echo protection, turn-off sequences, etc.) for half-duplex operation.