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