ITU-T Fax Standards

ITU V.21

The algorithm implemented is the ITU-T V.21modem recommendation for use in Group 3 facsimile. This transmits data at rates of up to 300 bps. This software will operate under the T.30 and T.4 protocols, using V.27ter. A complete software package will include an 8/9.6kHz sample interpolator to enable modem operation over ISDN or other applications that require 8kHz sampling.

V.21 is a Full-Duplex, Frequency Shift Keyed (FSK) modem, operating at a symbol rate of 300 symbols per second, with mean frequencies of 1,080±100 Hz and 1,750±100 Hz. Binary 0 is represented by the higher frequency (1,180Hz and 1,850Hz).

This product has been developed and shipped by SIGNALS+SOFTWARE on a number of platforms previously, both standalone and as part of a complete solution, and would be available customized to meet specific requirements.

For more information please contact our sales team.

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