|ITU-T V.34||Maximum bit rate of 33.6 Kbps|
|ITU-T V.17||Maximum bit rate of 14.4 Kbps|
|ITU-T V.29||Maximum bit rate of 9.6 Kbps|
|ITU-T V.27ter||Maximum bit rate of 4.8 Kbps|
|ITU-T V.21 ch.2||A portion of ITU-T V.21|
|AT F||AT commands for Fax|
|Fax Modem Protocols|
|GAO SuperG3 Fax||V.34, V.17, V.29, V.27ter, V.21 Channel 2, T.30|
|GAO Group 3 Fax||V.17, V.29, V.27ter, V.21 Channel 2, T.30|
|GAO Color Fax||V.34, V.17, V.29, V.27ter, V.21 Channel 2, T.30/T.30E, T.4|
ITU-T V.34 is the standard for dial up modems of up to 33,600bps. The fundamental design of V.34 incorporates a higher level of optional capabilities, intelligence, and adaptability than the lower V.series modems to make the best use of the available conditions. One of the most significant factors for increased bit rates is the use of the maximum bandwidth permitted by the channel. Unlike lower modem standards where nominal bandwidth was fixed with fixed carrier frequency, both the bandwidth and carrier frequencies are adaptive in V.34. Trellis coding and shell mapping make this modem a robust design for heavily impaired channels. The standard supports a half-duplex mode of operation for fax applications. GAO has V34 fax modem software (fax data pump) available for Super Group 3 (Super G3) fax application. GAO offers mature V.34 data modem software as well, deployed for several years.
GAO V.17 fax modem software implements the ITU-T V.17 recommendation for a two-wire modem for facsimile applications with rates up to 14,400bps. This international standard defines the operating sequences and modulation techniques to be used in high speed fax applications.
GAO V.17 fax data pump software module consists of transmitting functions and receiving functions which are called to transmit/receive bits in groups of 6, 5, 4, 3 (referred to as symbols) at a rate of 2400 symbols per second. It is also the modulation technique used in Group 3 fax (G3 fax) for fax data transfer, the V17 fax modem software provides 144000bps, 12000bps, 9600bps, and 7200bps trellis-coded modulation, and is operated in half duplex mode while transmitting/receiving data. More
GAO V.29 fax modem software implements the ITU-T V.29 Recommendation, which provides full-duplex data transmission at rates of 9600, 7200, and 4800bps over 4-wire leased lines. GAO's V29 modem data pump software has "quick connect" feature. It is also the modulation technique used in Group 3 fax (G3 fax) for fax data transfer at 9600bps and 7200bps on 2-wire lines. It consists of transmitting functions and receiving functions which are called to transmit/receive bits in groups of 2 or 3 (referred to as symbols) at rates of 1200 or 1600 symbols per second respectively. More
The GAO V27ter fax modem software implements the ITU-T V.27ter Recommendation, which is 4800bps and 2400bps modem, used in the general switched telephone network. It is the modulation scheme used in Group 3 facsimile (G3 fax) for image transfer at 4800bps and 2400bps. It consists of transmitting functions and receiving functions which are called to transmit/receive bits in groups of 2 or 3 (referred to as symbols) at a rate of 1200 or 1600 symbols per second respectively. More
GAO T.30 software implements ITU-T T.30 Recommendation, which is procedures for document facsimile transmission in the general switched telephone network.
GAO T30 software is targeted for fax application as fax handshaking protocol. It will establish and manage communications between two fax modems. There are five phases of operation covered: call set up, pre message procedure (selecting the communication mode), message transmission (including phasing and synchronization), post message procedure and call release.
GAO T30E software implements the procedure for the Group 3 (G3 fax) document facsimile transmission of continuous-tone color images. With T.30E, it will enable the efficient transmission of high quality, full color and gray-scale images over the general switched telephone network and other networks.
GAO's T38 fax over IP software allows the transfer of facsimile documents in real-time between two standard Group3 facsimile (G3 fax) terminals over the Internet or other networks using IP protocols. It is fully compliant with ITU-T T.38 fax relay specification, Procedures for real-time Group3 facsimile communication (fax) over IP networks while supporting V17/V29/V27ter/V21 ch.2 Standards. GAO's re-entrant implementation is optimized for multi-channel support on a single DSP. The "spoofing" function is included to prevent jitter, delay or lost packets. More
GAO's T.4 software implements ITU-T T.4 Recommendation, which defines the characteristics of Group3 facsimile terminals that enable black and white documents and also optionally color documents to be transmitted on the general switched telephone network, international leased circuits and the Integrated Services Digital Network (ISDN). GAO's T4 software will work with T.30 and V series standards to enable two fax modems communicate with each other.
For information on Fax Relay, please see GAO's Fax Relay Software.