Variable bandwidth voice and data telephone communication system

Claim 1

A telephone communication system comprising first and second telephone switchboards, means including standard telephone communication facilities interconnecting said first and second telephone switchboards and for temporarily allocating thereto a standard voice grade communication channel having an effective customer bandwidth of approximately 3000 Hertz, which channel may represent a single channel of a multi-channel carrier system, and means including switching means for facilitating the transmission of two separate voice grade communications of abbreviated bandwidth plus dial signals between plural telephones connected to said first and second telephone switchboards, said last-named means including first transmitting means for transmitting a first communication comprising voice grade signals at a first unique band of frequencies within said effective customer bandwidth and for modulating and transmitting at a unique band of frequencies within said effective customer bandwidth a first set of dial signals, both said voice grade signals and said dial signals being generated in a first telephone connected to one of said telephone switchboards, second transmitting means for modulating and transmitting a second communication comprising voice grade signals at a third unique band of frequencies within said effective customer bandwidth and for modulating and transmitting at a fourth unique band of frequencies within said effective customer bandwidth a second set of dial signals, both said second voice grade signals and said second set of dial signals being generated in a second telephone connected to one or another of said telephone switchboards, first receive means for receiving the unique band of voice grade signals transmitted by said first transmitting means, said first means further comprising a demodulator for demodulating the dial signals associated with said voice grade communication transmitted by said first transmitting means and for inputting the demodulated dial signals to the other one of said first and second telephone switchboards, said first receive means further comprising means for interpreting said dial signals and for generating a signal in response thereto to activate the ringer of a third telephone connected to the other one of said telephone switchboards, and second receive means including means for demodulating the said unique band of voice grade frequencies generated in said second transmitting means and the dial signals associated therewith and transferring said demodulated voice and dial signals to the other one of said one or another telephone switchboards for use in activating the ringer of a fourth telephone.

Claim 3

A system for use in combination with a common grade telephone voice channel comprising first means operative during a first mode of operation for limiting the physical speech band to a first reduced frequency band of a predetermined bandwidth and for providing said first reduced frequency band to combining means, said bandwidth being less than one-half of the bandwidth of said voice channel and said first band being situated at the low end of said channel, second means operative during said first mode of operation for limiting the physical speech band to a second reduced frequency band of a predetermined bandwidth, for translating said second band to a frequency band above said first band and in said channel and for providing said first reduced frequency band to said combining means, said second band being less than one-half of the bandwidth of said voice channel, said second means being operative during a second mode of operation for limiting the physical speech band to a third reduced frequency band which is slightly narrower than the bandwidth of said voice channel, switching means for disabling said first means during said second mode of operation and means for providing a first signal indicating the use of said first band and for providing a second signal indicating the use of said second or said third band, said combining means being operative for combining said first and second bands and said first and second signals during said first mode of operation and for combining said third band and said second signal during said second mode of operation.

Claim 4

A system for use in combination with a common grade telephone voice channel comprising first means operative during a first mode of operation for limiting the physical speech band to a first reduced frequency band of a predetermined bandwidth and for providing said first reduced frequency band to combining means, said bandwidth being less than one-half of the bandwidth of said voice channel and said first band being situated at the low end of said channel, second means operative during said first mode of operation for limiting the physical speech band to a second reduced frequency band of a predetermined bandwidth, for translating said second band to a frequency band above said first band and in said channel and for providing said first reduced frequency band to said combining means, said second band being less than one-half of the bandwidth of said voice channel, said second means being operative during a second mode of operation for limiting the physical speech band to a third reduced frequency band which is slightly narrower than the bandwidth of said voice channel, switching means for disabling said first means during said second mode of operation and means for providing a first signal indicating the use of said first band and for providing a second signal indicating the use of said second or said third band, said combining means being operative for combining said first and second bands and said first and second signals during said first mode of operation and for combining said third band and said second signal during said second mode of operation.

Claim 12

A system for use in combination with a common grade telephone voice channel comprising first means for limiting the physical speech band to a first reduced frequency band of a predetermined bandwidth and for providing said first reduced frequency band to combining means, said bandwidth being less than one-half of the bandwidth of said voice channel and said first band being situated at the low end of said channel, second means for limiting the physical speech band to a second reduced frequency band Of a predetermined bandwidth, for translating said second band to a frequency band above said first band and in said channel and for providing said second reduced frequency band to said combining means, said second band being less than one-half of the bandwidth of said voice channel, said first means and said second means including filtering means for shaping the amplitude characteristics of the bandwidths in which said speech bands are limited, the response of said speech band being increased by said filter from the low end of said reduced frequency band to a high response at the upper end of said reduced frequency band, and means for providing a first signal at a frequency within said channel and outside said first and second reduced frequency bands indicating the use of said first band and for providing a second signal at a frequency within said channel and outside said first and second reduced frequency bands indicating the use of said second band, said combining means being operative for combining said first and second bands and said first and second signals.

Claim 13

A system for use in combination with a common grade telephone voice channel comprising first means for limiting the physical speech band to a first reduced frequency band of a predetermined bandwidth and for providing said first reduced frequency band to combining means, said bandwidth being less than one-half of the bandwidth of said voice channel and said first band being situated at the low end of said channel, second means for limiting the physical speech band to a second reduced frequency band Of a predetermined bandwidth, for translating said second band to a frequency band above said first band and in said channel and for providing said second reduced frequency band to said combining means, said second band being less than one-half of the bandwidth of said voice channel, said first means and said second means including filtering means for shaping the amplitude characteristics of the bandwidths in which said speech bands are limited, the response of said speech band being increased by said filter from the low end of said reduced frequency band to a high response at the upper end of said reduced frequency band, and means for providing a first signal at a frequency within said channel and outside said first and second reduced frequency bands indicating the use of said first band and for providing a second signal at a frequency within said channel and outside said first and second reduced frequency bands indicating the use of said second band, said combining means being operative for combining said first and second bands and said first and second signals.

Claim 14

A system for use with a common grade telephone voice channel comprising first means for transmitting a first voice signal, second means for transmitting a second voice signal, third means for transmitting control signals and fourth means for transmitting at least one data signal, said first, second, third and fourth means including means to prevent interference between said voice signals, said control signals and said data signals during simultaneous transmission of all of said signals over a common grade telephone voice channel and said first, second, third and fourth means enabling intellible communications over standard full duplex grade telephone lines.

Claim 15

A system for use with a common grade telephone voice channel comprising first means for transmitting a first voice signal, second means for transmitting a second voice signal, third means for transmitting control signals and fourth means for transmitting at least one data signal, said first, second, third and fourth means including means to prevent interference between said voice signals, said control signals and said data signals during simultaneous transmission of all of said signals over a common grade telephone voice channel and said first, second, third and fourth means enabling intellible communications over standard full duplex grade telephone lines.