Paradyne Corporation

E Robert Lastinger, Jr

Robert Earl Scott

Robert E Scott

An echo canceler disabling system is associated with a cellular data communications device, such as a modem, which is utilized to communicate digital data over a cellular network for the purpose of enhancing digital data communications over the network. The echo canceler disabling system is configured to disable voice echo cancelers brought on-line during digital data transmission after call startup in order to prevent disruption of digital data communications by the voice echo cancelers. To deactivate the voice echo cancelers, the echo canceler disabling system is configured to transmit a tone at approximately 2100 Hz with 180 degree phase reversals to disable one or more echo cancelers brought on-line after the call startup. In architecture, the echo canceler disabling system includes a mechanism to detect a loss of signal synchronization, a mechanism to send an echo canceler disable tone, and a mechanism to send a retrain signal after the echo canceler disable tone is sent in order to reestablish signal synchronization.

Disabling of echo cancelers after call startup

A system is provided for automatically selecting the mode of communication between a plurality of multi-mode modems. A calling modem and an answering modem are disposed for intercommunication across an established communication link of a telephone network. The calling modem transmits a continuous calling signal across the established link, and the answering modem detects the calling signal and analyzes the calling signal to determine the configuration of the calling modem. In response, the answering modem generates and transmits an answering signal across the established link. The calling modem detects and analyzes the answering signal to determine the configuration of the answering modem. Finally, the system determines whether the established link passes through a PSTN, and if so, transmits a 2100 hertz tone across the established link. Otherwise, the system proceeds directly to the a modem training sequence.

System and method for automatically selecting the mode of communication

A cellular data gateway situated at a mobile telecommunications switching office (MSC) is provided for interconnecting an originating mobile modem of an analog cellular system to an answer modem of a public switched telephone network (PSTN) when one of the either the cellular side or the PSTN side of the connection is capable of a fast connection sequence. The cellular data gateway comprises a quick connect cellular modem connected to the MSC and configured for interfacing with the originating mobile modem. The cellular data gateway further includes a PSTN modem connected to the MSC and configured for interfacing with the answer modem of the PSTN. The cellular modem and the PSTN modem are interconnecting in the cellular data gateway as a back-to-back modem pair. As an important part of the invention, the cellular modem includes a mechanism for delaying the initiation of a fast connect sequence with the originating mobile modem until the PSTN modem has established a connection with the answer PSTN modem. The connection of the PSTN modems is preferably signaled to the cellular modem by a carrier detect (CD) signal, that is, at the establishment of the physical layer connection. This essentially ensures that the cellular side of the connection (between the originating mobile modem) and the cellular modem and the PSTN side of the connection (between the PSTN modem and the answer PSTN modem) have substantially synchronized connect messages. Alternatively, the connection of the PSTN modems can be signaled to the cellular modem by a connect signal from the PSTN modem.

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Lithia, FL, United States of America

E Robert Lastinger, Jr