Abstract: In order to enable V.34 fax relay communications over IP (“FoIP”) without increasing a gateway complexity, the gateway relays all types of fax control signals in demodulated form and transfers fax image type signals either as demodulated or as PCM encoded signal, based on a predetermined condition. The PCM data type is added to FoIP protocol to allow transferring PCM encoded fax image signals without exiting from FoIP mode of operation until the completion of a fax call. During a FoIP call, the communicating gateway determines whether the input fax signal is a ‘fax control signal’ or a ‘fax image’ type signal. If the gateway determines that the input signal is a fax control signal or supported fax image signal, it handles it in a traditional fax relay manner.

Abstract: A method is provided, for remotely updating information to, and controlling, a network appliance, which resides in a private location behind a network address translator (“NAT”), from a remote update server (“RUS”) that resides in a public location, the Internet Protocol (“IP”) address of, and a destination port number on, the RUS being known to the network appliance. The NAT may intermittently forward from the network appliance initialization messages that may be received at the RUS via its destination port. Responsive to the initialization messages being received at the RUS, the RUS may determine the source IP address and port number on the NAT from which the messages were received and send update data and/or control signal(s) via the destination port to the port number on the NAT.

Abstract: A voice encoder and decoder which attempt to minimize the effects of voice data packet loss, typically over wide area networks is provided. The voice encoder utilizes future data, such as the lookahead data typically available for linear predictive coding (LPC), to partially encode a future packet and to send the partial encoding as part of the current packet. The decoder utilizes the partial encoding of the previous packet to decode the current packet if the latter did not arrive properly.

Abstract: An improved speech processing system has a short-term analyzer, a target vector generator and a maximum likelihood, multi-pulse analyzer. The multi-pulse analyzer generates a plurality of sequences of equal amplitude, variable sign, variably spaced pulses. Each of the sequences have a different amplitude value and each of the pulses within each sequence have equal amplitudes but variable signs. The multi-pulse analyzer generates a signal corresponding to the sequence of equal amplitude, variable sign, variably spaced pulses which, according to maximum likelihood criteria, most closely represents the target vector. The maximum likelihood criteria are based on the cross-correlation of the target vector with an impulse response for the pulses in each sequence and on either a covariance matrix or an autocorrelation vector of the impulse response.

Abstract: A pitch determination device which separates at least each frame of the input speech signal into separate, lower resolution portions is provided. The pitch determination device includes a resolution lowering unit, a signal selecting unit and a pitch determination device. The resolution lowering unit has an input line on which the input speech signal is provided and K output lines, on each of which output lines, one of K lower resolution input signals is provided. The signal selecting unit has K input lines connected to the K output lines of the resolution lowering unit and has an output line on which is provided one of the K lower resolution signals which fulfill a predetermined quality criterion. The criterion is typically based on the energy content of the lower resolution signals. The pitch determination device has an input line connected to the output line of the signal selecting unit and an output line which provides a pitch value for the selected lower resolution input signal.

Abstract: A speech processing system and method are disclosed. In one embodiment of the present invention, the system includes at least a maximum likelihood quantization (MLQ) multi-pulse analysis unit operating on a target vector. The MLQ multi-pulse analyses unit typically determines an initial gain level for the multi-pulse sequence and performs single gain multi-pulse analysis (MPA) a number of times, each with a different gain level. The pulse sequence which most closely represents the target vector is provided as an output signal. In another embodiment, the system includes at least a pulse train multi-pulse analysis unit wherein the target vector is modeled as a series of pulse trains. Each pulse train comprises a plurality of single gain pulses, wherein each pulse is at a position which is a pitch value distance apart from the previous pulse in the pulse train. Combinations of maximum likelihood analyses with pulse trains are also part of the present invention.