Multiplex communications – Channel assignment techniques – Polling
Reexamination Certificate
1998-09-09
2003-04-08
Marcelo, Melvin (Department: 2733)
Multiplex communications
Channel assignment techniques
Polling
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.
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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.
Canon Kabushiki Kaisha
Fitzpatrick ,Cella, Harper & Scinto
Marcelo Melvin
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