Data communication system

Multiplex communications – Channel assignment techniques – Polling

Reexamination Certificate

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Details

C358S436000, C358S438000, C358S439000

Reexamination Certificate

active

06546020

ABSTRACT:

BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a data communication system, such as a facsimile system, capable of multi-polling communication between a polling transmitter and a polling receiver.
2. Related Background Art
Multi-polling communication is presently proposed by ITU-T, and an example of the protocol therefor is shown in FIG.
12
. As shown in
FIG. 12
, a DIS signal contains a signal (ms bit) indicating the presence or absence of the multi-selection function, and, if the signal is “1” indicating the presence of the multi-selection function, a polling-receiver sets the ms bit of a DTC signal at “1” when it requests the multi-polling.
On the other hand, a polling-transmitter transmits an EOS (end-of-selection) signal after the transmission of a document, and the polling-receiver transmits a DTC signal in case of requesting a next document or a MCF signal in case of not requesting the next document.
In the above-explained configuration, however, in case of conducting the next polling reception, the polling-receiver is incapable of informing the polling-transmitter that the document has been correctly received. Also, training operations cannot be effectively selected since RTN and RTP signals cannot be transmitted.
After the transmission of the EOS signal, the polling-transmitter also receives SEP/DTC signal, which is not defined in the conventional T-30 protocol. Therefore, a trouble may be generated in the communication.
SUMMARY OF THE INVENTION
In consideration of the foregoing, an object of the present invention is to provide a data communication system capable of effectively executing the multi-polling communication.


REFERENCES:
patent: 5418624 (1995-05-01), Ahmed
patent: 5671270 (1997-09-01), Yoshida
patent: 5748714 (1998-05-01), Yoshida
patent: 6072597 (2000-06-01), Yoshida
patent: 6104504 (2000-08-01), Imai et al.
patent: 6281987 (2001-08-01), Yoshida
patent: 6414965 (2002-07-01), Yoshida
patent: 0 637 164 (1995-02-01), None
patent: 0 652 668 (1995-05-01), None
patent: 0 674 424 (1995-09-01), None
patent: 902584 (1999-03-01), None
International Telecommunication Union: “ITU-T. Rec. T.30 Amendment 3, Terminals for Telematic Services”, ITU-T Telecommunication Standardization Sector of ITU, Jun. 1998.
International Telecommunication Union: “ITU-T. Rec. T. 30 Amendment 1: Terminals for Telematic Services:”, ITU-T Telecommunication Standardization Sector of ITU, Jul. 1997.
International Telecommunication Union: “ITU-T Rec. T.30”, ITU-T Telecommunication Standardization Sector of ITU, Jul. 1996.
US Patent Application Ser. No. 09/172,059 filed Oct. 14, 1998.

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