Abstract: In a gateway router the length of the play-out buffer in VBD mode is not set at a previously established value. Instead the length of the play-out buffer in VBD mode is determined by the length of the buffer in the previous audio mode. When the system switches from audio mode to VDB mode, the length of the play-out buffer in audio mode is noted. The length of the play-out buffer in VBD mode is then set equal to its length in the prior audio mode plus a dilation factor. An audio concealment algorithm (which fills in gaps caused by missed packets) is used during the transition from audio to VDB to conceal any transition glitch during the answer tone.

Abstract: A two stage compression sub-system for clear channel data. The front stage of the compressing sub-system is an octet based repeat compressor (for example a flag compressor). The second stage is dictionary based compressor (for example Lempel-Ziv (LZ) or Huffmann). Data is compressed using several different techniques, and the technique that provides the best compression is used for each particular packet.

Abstract: A network device and a method for its operation are disclosed. The network device has a first interface to a client device to allow reception of client device signals and a second interface to a packet network to allow transmission and reception of modem relay signals. A processor translates between modem relay signals received or transmitted on the second interface and client device signals received or transmitted on the first interface. In one implementation the modem relay originator and the client device are collapsed into one device and the first interface is implemented as a virtual interface.

Abstract: Method and apparatus are described for differential MoIP bring-up and compression negotiation. A first differential, and, more particularly, overlapping, bring-up method involves initiating a bring-up of a first layer associated with a first modem; imposing a time delay; after the time delay, initiating a bring-up of a second layer associated with a second modem; and delaying completion of the first layer bring-up associated with the first modem until substantial completion of the second layer bring-up associated with the second modem. Two alternative differential, and, more particularly, sequential, V.8 modem relay link bring-up methods involve first bringing up a physical layer at a first leg while delaying bring-up of the physical layer of the second leg until completion of the bring up of the physical layer at the first leg, and thereafter completing XID exchange.

Abstract: A modem data aggregating gateway that supports modem relay functionality for permitting reliable switching of modem traffic between a VoIP network and a data packet switch Internet Protocol (IP) network, s.a. the Internet. The modem relay aggregator may receive modem data encapsulated as Voice over IP (VoIP) data packets in accordance with a Simple Packet Relay Transport (SPRT) mechanism. The packet data may be error corrected and/or decompressed before being repackaged for forwarding to the ultimate destination. In the event that the destination is itself an IP device, the modem relay aggregator may forward the packets directly over the IP network. As a result, if the destination of a modem call is an IP device (such as a Web site or other Internet-enabled device) the technique eliminates two points from a processing path in which digital signal processing (DSPs) would otherwise have to perform modem protocol processing. Otherwise, minimal modem reformatting can be performed at the aggregation point.

Abstract: A modem data aggregating gateway that supports modem relay functionality for permitting reliable switching of modem traffic between a VoIP network and a data packet switch Internet Protocol (IP) network, s.a. the Internet. The modem relay aggregator may receive modem data encapsulated as Voice over IP (VoIP) data packets in accordance with a Simple Reliable Protocol Transport (SRPT) mechanism. The packet data may be error corrected and/or decompressed before being repackaged for forwarding to the ultimate destination. In the event that the destination is itself an IP device, the modem relay aggregator may forward the packets directly over the IP network. As a result, if the destination of a modem call is an IP device (such as a Web site or other Internet-enabled device) the technique eliminates two points from a processing path in which digital signal processing (DSPs) would otherwise have to perform modem protocol processing. Otherwise, minimal modem reformatting can be performed at the aggregation point.

Abstract: The present invention is a two-pass method and apparatus for achieving maximal data compression for a voice frame modem relay channel between two endpoint modems. The method includes transitioning the channel from a voice mode to a modem relay mode of operation; negotiating maximal compression parameters for either of two endpoint segments; communicating the same from one segment to the other; and then negotiating maximal end-to-end data compression parameters based upon the negotiated endpoint segment compression parameters. The end-to-end negotiation preferably involves re-negotiating one of the endpoint segments.

Abstract: Method and apparatus for synchronizing two de/compression modems, e.g. V.42bis modems, in a voice frame network, the modems each being connected with a corresponding gateway to form a corresponding segment, are described. The method includes terminating the physical layer at either end of the corresponding gateways; negotiating at either gateway a physical layer and error-correcting data link layer with the corresponding modem; sending from either gateway to an associated modem in response to any poll command therefrom a not-ready message; signaling the other gateway when physical layer and error-correcting data link layer negotiations have been completed; and when each gateway has signaled the other that negotiations have been completed, halting the not-ready message-sending and sending instead a ready message to a corresponding modem, whereby synchronized compressed and decompressed data transmissions between the modems commences on a reliable transport.