Modem control method
AssigneeMatsushita Graphic Communication Systems, Inc.
InventorsNobuhiko Noma, Tsukasa Sakai, Genzou Takagi
Life of this patent
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Abstract
When carrying out pre-processing of image signal transmission using the control channel of a full-duplex modem and switching image signal transmission to the primary channel of a half-duplex modem, the answer modem stops the transmission carrier upon confirmation that all “1” signals with 40 bit or more have been received from the calling modem, restarts the reception of all “1” signals after the elapse of a certain period of time, confirms the end of all “1” signals and switches to the primary channel.
Claims15
A modem control method, comprising the steps of:
- confirming whether unit signals received from the calling modem continue for a prescribed number of bits or not;
- turning off the transmission carrier if said unit signals continue for a prescribed number of bits;
- holding the processing in standby mode for a certain period of time after the transmission carrier has been turned off;
- restarting the process after a certain period of time, receiving unit signals, and switching from the reception of the control channel to the reception of the primary channel when the reception of unit signals is completed.
A modem control method which carries out the pre-processing of image signal transmission in facsimile transmissions using a full-duplex modem and then performs image signal transmission by a half-duplex modem, wherein if, upon termination of the full-duplex modem, a request for termination from the calling modem to transmit unit signals made up of prescribed bits continuously, a prescribed number of said unit signals are received from the calling modem first, the transmission to the calling modem is stopped, the reception of said unit signals from the calling modem is ignored for a certain period of time, then the reception of said unit signals is restarted and the process is switched over to the reception by the half-duplex modem when the reception of these unit signals is completed.
A modem control method which uses an ITU Recommendation V.34 facsimile modem, carries out the pre-processing of image signal transmission using the control channel of a full-duplex modem in compliance with the ITU Recommendation T.30 ANNEX-F, and carries out image signal transmission by switching to the primary channel of a half-duplex modem, wherein upon reception of a termination request signal of at least 40 all “1” bits indicating a request for control channel termination from the calling modem, after confirming that signals received from the calling modem are all “1” signals with 40 bits or more, the transmission to the calling modem is stopped, the reception of all “1” signals from the calling modem is ignored, then the reception of all “1” signals is restarted, and the process is switched over to the primary channel after confirming the end of reception of those all “1” signals.
A modem control apparatus, comprising:
- signal confirmation means for confirming whether a signal from the calling modem is a unit signal or not;
- carrier-off indication means for indicating transmission carrier off based on the output from said signal confirmation means;
- processing standby/restart indication means for controlling indications of processing standby and processing restarting based on the output from the carrier off indication means;
- switching indication means for switching from the reception of the control channel to the reception of the primary channel based on the output from the signal confirmation means after restarting the processing.
Dependencies are inferred from the claim text.