Data and speech transmission device

• US 5,365,576 A
• Filed: 02/27/1992
• Issued: 11/15/1994
• Est. Priority Date: 02/27/1991
• Status: Expired due to Term

• Current Assignee: Ricoh Company Limited
• Original Assignee: Ricoh Company Limited
• Inventors: Hata, Masato, Tsumura, Mihoji
• Primary Examiner(s): Peng, John K.
• Assistant Examiner(s): Wu, Daniel J.
• Application Number:
  US07/842,553
• Time in Patent Office: 992 Days
• Field of Search: 379/93, 379/100, 379/53, 379/54, 379/96-99, 358/85, 358/434
• US Class Current: 379/93.08
• CPC Class Codes: H04M 11/064 Data transmission during pauses in telephone conversation

Abstract

A device for making efficient use of the free time between speech transmissions and binary coded data transmissions, the device including a switch which will automatically output both the binary coded data and the outgoing speech signals to a telephone line and which will connect to the device, each of the incoming signals received from the telephone line. The device includes an outgoing transmission block and an incoming transmission block. The outgoing transmission block outputs speech signals or data signals selectively after mixing the signals with one of two tone signals of different frequencies. The incoming transmission block first identifies incoming signals by two bandpass filters and then, depending on the identity of the signals, selectively connects the incoming signals either to a speech restoration circuit or to a data restoration circuit.

Claims

1. A data and speech transmission device comprising:

an outgoing transmission block having a speech transmission tester for detecting input of speech signals and on receipt of said speech signals simultaneously issuing a transmission interrupt signal, a data transmission controller for receiving data signals, said data transmission controller being connected to said speech transmission tester for receiving said transmission interrupt signal, a timer connected to said speech transmission tester for outputting a transmission enabling signal to said data transmission controller a fixed period of time after said speech transmission tester has detected an absence of said speech signals input, means for generating two tone signals each of said tone signals having a different frequency, a first mixing means for mixing said speech signals with one of said tone signals, and a second mixing means for mixing said data signals with a second one of said tone signals, said second mixing means being connected to said data transmission controller for receiving said data signals, a switch connected to said speech transmission tester for selectively outputting said mixed speech signals and said mixed data signals to a telephone line in response to a control signal from said speech transmission tester; and

an incoming transmission block connected to said outgoing transmission block for receiving incoming speech and data signals, said incoming transmission block including two band-pass filters for receiving said incoming signals, each of said filters corresponding in frequency to one of said two tone signals, a comparator connected to said filters for identifying signals output from said filters, an incoming transmission switch for receiving said incoming signals, a speech restoration circuit and a data restoration circuit, said restoration circuits being connected to said incoming transmission switch, and a data and speech controller connected to said comparator, said controller outputting a control signal to said incoming transmission switch for selectively connecting said incoming signals either to said speech restoration circuit or said data restoration circuit, whereby said incoming signals are restored to their original form for input to a telephone or a computer, respectively.

2. The data and speech transmission device according to claim 1 wherein said outgoing transmission block and said incoming transmission block are connected by an isolator which in turn is connected to a telephone line.

3. The data and speech transmission device according to claim 1 in which said timer functions as an output timing delay means for said data signals only, said timer having no processing function in respect of timing of output of said speech signals.

4. The data and speech transmission device according to claim 1 in which said two tone signals are both set to frequencies close to an upper limit value of a telephone line carrier wave band.

5. The data and speech transmission device according to claim 1 in which an artificial noise generator transmits noise to a telephone receiver whenever said data signals are being received.

6. The data and speech transmission device according to claim 1 wherein said device is connected by way of a telephone network to a host computer, said host computer including speech signal output means.

7. A data and speech transmission device comprising:

first mixing means for combining a first tone signal with analog speech signals;

second mixing means for combining a second tone signal of different frequency with digital data strings after said data strings have been converted to analog data signals;

a first switching device connected to said first and second mixing means for selectively transmitting either said speech or said data signals to a telephone line;

a second switching device connected to said telephone line for receiving incoming signals, said second switching device including two notch filters, each of said notch filters corresponding in frequency to one of said two tone signals, said notch filters being connected to receive said incoming signals;

two band pass filters, each of said band pass filters corresponding in frequency to one of said two tone signals, said band pass filters being connected to receive said incoming signals from said telephone line;

a frequency tester, connected to said band pass filters for determining a tone signal frequency for said incoming signals and generating a control signal; and

said second switching device receiving said control signal from said frequency tester and in response to said control signal, selectively outputting signals from one of said notch filters which matches said incoming tone signal frequency, whereby said signals are input either to a telephone or a computer, depending upon said selection of said second switching device.

8. The data and speech transmission device according to claim 7 in which both said first switching device and also said second switching device are normally connected to enable the input and output of said speech signals.

9. The data and speech transmission device according to claim 7 in which said second switching device remains connected to the incoming speech side whenever the two tone signals included as part of the incoming signal elements remain below a specified threshold level

10. The data and speech transmission device according to claim 7 which is connected by way of a telephone network to a host computer.