Pulse or digital communications – Transceivers – Transmission interface between two stations or terminals
Reexamination Certificate
1998-03-20
2001-01-09
Chin, Stephen (Department: 2732)
Pulse or digital communications
Transceivers
Transmission interface between two stations or terminals
C375S222000, C375S259000
Reexamination Certificate
active
06173010
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a system and a method for initializing an apparatus for transferring asymmetrical data, and more particularly, to a system and method for reducing initialization time of an apparatus used for transferring asymmetrical data using previously stored characteristics of the transfer line.
2. Description of the Related Art
A system for transferring asymmetrical data is used as part of a high speed MODEM having a transferring speed of at least 9,600 bps. The bandwidth of a telephone line—connected to the MODEM—is divided into a low speed communication line and a high speed communication line, which are both asymmetrical communication lines. Initially, data is transferred at a speed of about 300-450 bps in the low speed communication line and later at a speed of at least 9,600 bps in the high speed communication line. The data is received and transferred simultaneously by the above mentioned division of the bandwidth into two.
FIG. 1
is a block diagram of a system for transferring asymmetrical data. A mother apparatus
100
is connected to a child apparatus
102
by a telephone line
101
. The mother apparatus receives digital data from and transfers data to the child apparatus
102
. In this example, the mother apparatus
100
is installed in a telephone office. The child apparatus
102
is installed in a subscriber's home. occasionally data transfer may be affected by an interruption in the power supply to the mother apparatus
100
or the telephone line
101
. In such a case, the apparatus for transferring asymmetrical data shown in
FIG. 1
is initialized. The initialization takes place after the interruption ceases.
FIG. 2
is a flowchart showing a conventional method of initializing the apparatus shown in FIG.
1
. In this flowchart, a transfer line uses a frequency band between 30-1104 kHz which has been divided into 248 sub-channels (4.3125 kHz per sub-channel) to transmit data between a mother and a child apparatus.
In step
220
the telephone line is optimized by the mother apparatus
100
transferring a test signal to the child apparatus
102
, as part of a basic communication. In step
230
, the attenuation of the noise and signal in each of the 248 sub-channels constituting the frequency band is analyzed. In step
240
, 0-15 data bits to be transferred are assigned to each of the sub-channels using the analysis made in the step
230
. In step
250
, the assigned data bits are transferred to the child apparatus
102
—thereby performing a normal communication.
In the above-mentioned initialization process of
FIG. 2
, unnecessary time is consumed since the characteristics of the frequency band, used to transmit data on the transfer line, are examined during every initialization after an interruption.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide a system and a method for initializing an apparatus for transferring asymmetrical data using the characteristics of the transfer line known a priori, instead of reanalyzing the characteristics of the transfer line in the case where characteristics of the transfer line are expected to remain unchanged.
In order to achieve the above object, the method for initializing an apparatus for transferring asymmetrical data on a transfer line using a frequency band according to the present invention comprises: (a) determining whether data bit assignment tables assigning data based on the channel characteristics of the transfer line are effective and (b) transferring data based on stored characteristics of the transfer line without reanalyzing, when the data bit assignment tables are determined to be effective in step (a).
Another aspect of this invention is a system for initializing an apparatus for transferring asymmetrical data using a transfer channel comprising a frequency band comprising a microprocessor and a RAM, wherein the microprocessor determines whether data bit assignment tables stored in the RAM is effective after an interruption in communication based on the presence of corrected records in specific areas of the data bit assignment tables, wherein further communication is based on the data bit assignment tables when they are determined to be effective, and wherein the transfer line is reanalyzed to create new data bit assignment tables when the data bit assignment tables are not effective and said new data bit assignment tables are used for further communication.
REFERENCES:
patent: 5794254 (2000-08-01), McClain
patent: 5870438 (1999-02-01), Olafsson
patent: 6064692 (2000-05-01), Chow
patent: 6101585 (2000-08-01), Brown et al.
patent: 4-271557 (1992-09-01), None
patent: 5-284321 (1993-10-01), None
patent: 9-51328 (1997-02-01), None
Nikkei Electronics, No. 676, Nikkei BP Company, Nov. 18, 1996, pp. 89-108.
Chin Stephen
Ha Dac V.
Samsung Electronics Co,. Ltd.
Sughrue Mion Zinn Macpeak & Seas, PLLC
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