Data communication apparatus

• US 6,522,731 B2
• Filed: 12/13/1999
• Issued: 02/18/2003
• Est. Priority Date: 04/24/1998
• Status: Expired due to Fees

• Current Assignee: Mitsubishi Denki Kabushiki Kaisha (Mitsubishi Electric Corporation)
• Original Assignee: Mitsubishi Denki Kabushiki Kaisha (Mitsubishi Electric Corporation)
• Inventors: Matsumoto, Wataru
• Primary Examiner(s): Ramakrishnaiah, Melur
• Application Number:
  US09/445,599
• Publication Number:
  US 20020067811A1
• Time in Patent Office: 1,163 Days
• Field of Search: 379/90.01, 379/93.08, 379/93.09, 379/93.05, 379/93.28, 379/93.31, 379/93.06, 379/252, 379/283, 370/210, 370/486, 370/487, 370/493, 370/494, 375/222, 375/219, 375/377
• US Class Current: 379/93.08
• CPC Class Codes: H04L 2012/6478 Digital subscriber line, e.g. DSL, ADSL, HDSL, XDSL, VDSL
• CPC Class Codes: H04M 11/062 using different frequency bands for speech and other data
• CPC Class Codes: H04M 3/30 for subscriber's lines , for the local loop

Abstract

An on-hook/off-hook detection circuit (61) detects the voltage level of a telephone line C and thus detects whether the audio band communication using the telephone line C is in on-hook state or in off-hook state thereby to output a status detection signal (81). TEQ (63), FEQ (66) and a constellation encoder gain scaling (67), based on the particular status detection signal (81), conducts the data communication by the adaptive equalization, the bit allocation and the gain allocation in the time domain and the frequency domain using separate tables (75 to 80) for on-hook and off-hook states. In on-hook state where no telephone is used, the transmission subcarrier is extended or shifted up to the neighborhood of-the audio band and the communication is conducted using up to the audio band.

Claims

1. A data communication apparatus which can conduct data communication using the telephone line for audio band communication, comprising:

a detection unit which detects whether the audio band communication is being conducted on said telephone line; and

a communication unit which conducts data communication through said telephone line with different characteristics for the active audio band communication and the inactive audio band communication based on the detection output of said detection unit, wherein said communication unit includes;

an active audio band communication coefficient table for storing the equalization coefficients in the case where the audio band communication is being conducted on said telephone line;

an inactive audio band communication coefficient table for storing the equalization coefficients in the case where the audio band communication is not being conducted on said telephone line;

an equalizer for equalizing, based on the detection output of said detection unit, the received signal of the data communication by said active audio band communication coefficients in the case where the audio band communication is being conducted on said telephone line, and the received signal of the data communication by said inactive audio band communication coefficients in the case where the audio band communication is not being conducted on said telephone line; and

wherein the data communication is conducted through said telephone line with different noise removal characteristics between the active audio band communication and the inactive audio band communication and gain level is adjusted each time separately for on-hook and off-hook states so that gain level at each time in the time domain does not affect the gain level at other times in the time domain.

2. The data communication apparatus according to claim 1, wherein the data communication is the ADSK data communication of discrete multitone modem type, and the apparatus is an ADSL communication modem.

3. A data communication apparatus according to claim 1, which conducts data communication using a telephone line for audio band communication comprising:

conducting data communication through said telephone line using an operating band, wherein

said operating band does not interfere with audio band communication when said detection unit detects that audio band communication is being conducted, and

said operating band being shifted or expanded up to the neighborhood of the audio band interfering with said audio band communication when said detection unit detects that audio band communication is not being conducted.

4. The data communication apparatus according to claim 3, wherein the data communication is the ADSL data communication of discrete multitone modem type, and the apparatus is an ADSL communication modem.

5. The data communication apparatus according to claim 3, wherein said operating band is expanded up substantially to the audio band of 4 kHz when said detection unit detects that audio band communication is not being conducted.

6. A data communication apparatus according to claim 1, for conducting data communication over a standard telephone line comprising:

a communication circuit which conducts data communication by equalizing a signal received from said phone line according to a set of coefficients, said set of coefficients being determined based on a determination of whether or not audio band communication is being conducted on said telephone line, said determination being made based on a detected dc voltage level of said telephone line.

7. The data communication apparatus according to claim 6, wherein said set of coefficients is determined based on a stored coefficient table which stores a set of equalization coefficients to be used when audio band communication is being conducted on said telephone line, and a separate set of equalization coefficients to be used when audio band communication is not being conducted on said telephone line.

8. The data communication apparatus according to claim 6, wherein said sets of equalization coefficients are determined by carrying out a training before the start of data communication.

9. The data communication apparatus according to claim 8, wherein said sets of equalization coefficients are determined according to said training in order to secure substantially the same gain for each time component and each frequency component, whether or not audio band communication is being conducted on said telephone line during data communication.

10. A data communication apparatus according to claim 1, for conducting data communication over a standard telephone line comprising:

a communication circuit which conducts data communication by allocating bits to each channel, wherein the bits allocated to each channel are determined according to whether or not audio band communication is being conducted on said telephone line.

11. The data communication apparatus according to claim 10, wherein bits are allocated to each channel based on a bit allocation table which stores a bit allocation for each channel for occasions when audio band communication is being conducted, and which stores a bit allocation for each channel for occasions when audio band communication is not being conducted.

12. The data communication apparatus according to claim 11, wherein said bit allocation table is generated by carrying out a training before the start of data communication.

13. The data communication apparatus according to claim 10, wherein a dc voltage level of said telephone line is detected in order to determine whether or not audio band communication is being conducted on said telephone line.

14. A data communication apparatus according to claim 1, for conducting data communication over a standard telephone line comprising:

a communication circuit which conducts data communication by allocating gain to each channel, wherein the gain allocated to each channel is determined according to a determination of whether or not audio band communication is being conducted on said telephone line, said determination being made based on a detected dc voltage level of said telephone line.

15. The data communication apparatus according to claim 14, wherein gain is allocated to each channel based on a gain allocation table which stores a gain allocation for each channel for occasions when audio band communication is being conducted, and which stores a gain allocation for each channel for occasions when audio band communication is not being conducted.

16. The data communication apparatus according to claim 15, wherein said gain allocation table is generated by carrying out a training before the start of data communication.

17. The data communication apparatus according to claim 1, wherein said detection unit detects whether or not the audio band communication is being conducted based on a detected dc voltage level of said telephone line.

18. The data communication apparatus according to claim 1, wherein said inactive audio band communication conducted by said communication unit uses up to the neighborhood interfering with an operating band of said audio band communication.

19. A data communication apparatus which can conduct data communication using the telephone line for audio band communication, comprising:

a detection unit which detects whether the audio band communication is being conducted on said telephone line; and

a communication unit which conducts data communication through said telephone line with different characteristics for the active audio band communication and the inactive audio band communication based on the detection output of said detection unit, wherein said communication unit includes;

an active audio band communication bit allocation table for storing the bit allocation for each channel in the case where the audio band communication is being conducted on said telephone line;

an inactive audio band communication bit allocation table for storing the bit allocation for each channel in the case where the audio band communication is not being conducted on said telephone line;

a bit allocator for allocating, based on the detection output of said detection unit, the bits to each channel according to said active audio band communication bit allocation table in the case where the audio band communication is being conducted on said telephone line, and the bits to each channel according to said inactive audio band communication bit allocation table in the case where the audio band communication is not being conducted on said telephone line; and

wherein the data communication is conducted through said telephone line with different bit allocation characteristics for each channel between the active audio band communication and the inactive audio band communication and gain level is adjusted each time separately for on-hook and off-hook states so that gain level at each time in the time domain does not affect the gain level at other times in the time domain.

20. The data communication apparatus according to claim 19, wherein the data communication is the ADSL data communication of discrete multitone modem type, and the apparatus is an ADSL communication modem.

21. A data communication apparatus which can conduct data communication using the telephone line for audio band communication, comprising:

a detection unit which detects whether the audio band communication is being conducted on said telephone line;

a communication unit which conducts data communication through said telephone line with different characteristics for the active audio band communication and the inactive audio band communication based on the detection output of said detection unit, wherein said communication unit includes;

an active audio band communication gain allocation table for storing the gain allocation for each channel in the case where the audio band communication is being conducted on said telephone line;

an inactive audio band communication gain allocation table for storing the gain allocation for each channel in the case where the audio band communication is not being conducted on said telephone line;

a gain allocator for allocating, based on the detection output of said detection unit, the gains to each channel according to said active audio band communication gain allocation table in the case where the audio band communication is being conducted on said telephone line, and the gains to each channel according to said inactive audio band communication gain allocation table in the case where the audio band communication is not being conducted on said telephone line; and

wherein the data communication is conducted through said telephone line with different gain allocation characteristics for each channel between the active audio band communication and the inactive audio band communication and gain level is adjusted each time separately for on-hook and off-hook states so that gain level at each time in the time domain does not affect the gain level at other times in the time domain.

22. The data communication apparatus according to claim 21, wherein the data communication is the ADSL data communication of discrete multitone modem type, and the apparatus is an ADSL communication modem.

23. The data communication apparatus according to claim 21, wherein said detection unit detects whether or not the audio band communication is being conducted based on a detected dc voltage level of said telephone line.

24. The data communication apparatus according to claim 21, wherein said inactive audio band communication conducted by said communication unit uses up to the neighborhood interfering with an operating band of said audio band communication.

25. A data communication apparatus which can conduct data communication using the telephone line for audio band communication, comprising:

a detection unit for detecting whether the audio band communication is being conducted on said telephone line; and

a communication unit for conducting, based on the detection output of said detection unit, the data communication using a predetermined band not interfering with the audio band communication in active audio band communication mode, and the data communication using up to the neighborhood of the audio band in the inactive audio band communication mode, said communication unit including, only on the transmission side, a filter for removing the frequency band of the ring tone signal for transmitting the request for the audio band communication to the receiving end.

26. The data communication apparatus according to claim 25, wherein the data communication is the ADSL data communication of discrete multitone modem type, and the apparatus is an ADSL communication modem.

27. A data communication apparatus which conducts data communication using a telephone line for audio band communication comprising:

a detection unit which detects whether the audio band communication is being conducted on said telephone line; and

a communication unit which conducts data communication through said telephone line using an operating band, wherein

said operating band does not interfere with audio band communication when said detection unit detects that audio band communication is being conducted, and

said operating band being shifted or expanded up to the neighborhood of the audio band interfering with said audio band communication when said detection unit detects that audio band communication is not being conducted,

wherein said operating band is expanded up to the audio band of 4 kHz when said detection unit detects that audio band communication is not being conducted, and wherein

said communication unit includes a filter in a transmission side for removing the frequency band of the ring tone signal for transmitting the request for the audio band communication to the receiving end.