Abstract: A voice packet multiplexer with a voice transit switching function, which is connected to a PBX in an office. It detects an originating logical channel according to digits sent from the PBX, and sets, when transmitting a signal packet or voice packet, the detected originating logical channel in its address field. It also stores an originating logical channel while receiving a packet from a packet communication network. It further extracts an office number from a received packet containing the digit information, makes a decision whether the office number is the number of its own office or of another office, and retrieves, if it is of the another office, a terminating logical channel for establishing connection with that office. To carry out the voice transit switching after determining the terminating logical channel, it transmits a packet after translating its address field into the terminating logical channel or into the originating logical channel.

Abstract: Identification information of a speech spurt, hangover and pause is used to indicate that a digital voice signal is the speech spurt, hangover or pause. While the identification information of a speech spurt, hangover and pause is indicative of the speech spurt, a voice level adjuster does not attenuate the digital voice signal, and the voice signal/third signal combiner mixes it with a third signal which undergoes the maximum attenuation through a third signal level adjuster. While the identification information of a speech spurt, hangover and pause is indicative of the hangover, the voice level adjuster gradually attenuates the digital voice signal. This is because the level of the voice signal is expected to be high in the first half of the hangover period, but to decay in its latter half to such a level that it is dispensable for speech recognition.

Abstract: A speech spurt detecting apparatus for detecting speech spurts in a voice signal has a storage for storing an input voice signal. A decision portion determines speech spurt sections and mute sections using a threshold value and sets one of the mute sections at a latter part of a hangover time. A mute level statistical processor estimates the noise distribution of a signal in the mute sections. A speech spurt detecting threshold value decision portion receives the average and the variance of the noise distribution from the mute level statistical processor and approximates the noise distribution to a gamma distribution to decide a speech spurt detecting threshold. A speech spurt transmitting portion outputs the voice signal in the speech spurt sections from the storage. A speech spurt level statistical processor carries out statistical processing of the speech spurt sections.