V.90 Modem Software (V.90 soft modem, V.90 softmodem

By: Gao Research  06-Dec-2011
Keywords: Modem, Analog Modem, Digital Modem,

GAO V.90 software module implements the V.90 ITU-T recommendation for modems that can connect at data rates of up to 56 Kbps. The standard specifies a pair of high-speed modems, one digital and the other analog, which are designed for Internet use. The V.90 Server Modem is a digital modem with a maximum bit rate of 56 Kbps transmit and 33.6 Kbps receive. The V.90 Client Modem is an analog modem with a maximum bit rate of 56 Kbps receive, 33.6 Kbps transmit.

Most ISPs are digitally connected both to the Internet and to the telephone company's central office (CO). When this is the case, there is a clear digital connection downstream from the ISP's modem to the CO's line card that serves the user and contains a digital to analog converter.

The result of having this digital connection is that an analog to digital conversion, and therefore quantization noise, is avoided between the ISP and CO. Without the limits imposed by quantization noise, it is possible to achieve downstream connection speeds of up to 56 Kbps downstream. Because most users are not digitally connected to the CO, an analog to digital conversion and the associated quantization noise cannot be avoided in the upstream direction. This means that V.34 modulation techniques must be used and upstream speeds are still limited to 33.6 Kbps.

Copyright © GAO Research Inc. 2011 All Rights Reserved

Keywords: Analog Modem, Digital Modem, Modem,

Other products and services from Gao Research


T.38 Fax relay protocol (T38 FoIP protocol

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.


Voice Over IP Software (VoIP Software

The Packet Protocol module receives signaling information that has been interpreted by the Telephony Processing module and converts it from the telephony signaling protocols to the specific packet signaling protocol that is used to set up connections over the data network. GAO VoIP products detect when packets are lost and reconstructs them either by repeating information in subsequent frames or using an upper layer protocol.


V.92 Modem Software (V.92 soft modem, V.92 softmodem

By employing pulse code modulation in the upstream direction, V.92 supplies a data rate of up to 48kbps ?a significant improvement over V.90 which uses quadrature amplitude modulation , the same upstream modulation as V.34, for a maximum speed of 33.6kbps. The shortened start-up time is accomplished by buffering information on past connections then, when a match is found, handshaking can immediately begin at a previously negotiated rate.


G3 Fax (Group 3 Fax) Software

V.34, V.17, V.29, V.27ter, V.21 Channel 2, T.30.