System for recognizing bidirectional communication over parrallel data lines by further sending data transmission request and notification indicating reverse direction transmission is possible to second device
First Claim
1. A bidirectional communication recognition method for a first device in a communication system for transmitting data in a forward direction from the first device to a second device over parallel data lines of a parallel interface, and transmitting data in a reverse direction from the second device to the first device over the parallel data lines, the method comprising:
- writing specific data to a data register provided in the first device, which outputs data written during forward direction transmission as parallel signals to the parallel data lines,reading contents of the data register, andcomparing the written specific data with the read contents to determine whether the read contents and the written data are different,if the read contents and the written data are determined to be different, recognizing that bidirectional communication of the first device and the second device at a predetermined system over the parallel data lines is possible without operator intervention,if the read contents and the written data are determined to be identical recognizing that the bidirectional communication is not possible without operator intervention, andwhen the read contents and the written data are determined to be different, sending a data transmission request and a notification indicating that data line reverse direction transmission is possible from said first device to said second device.
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Accused Products
Abstract
A bidirectional communication method, bidirectional communication device and storage medium for automatically setting the communication mode without complications to the user and not causing the malfunctioning of the computer system and the printer are disclosed. The control register of the personal computer is used to set data reception from the laser printer in a byte mode. A specific data is written to the data register, and the value of the data register is read. If the value of the data register is not the specific data, it is recognized that the personal computer can be set to the byte mode. If, on the other hand, the read value of the data register is the specific data, another specific data is written to the data register, then the value of the data register is read, and if the value of the data register is another specific data, it is recognized that the personal computer cannot be set to the byte mode.
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Citations
31 Claims
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1. A bidirectional communication recognition method for a first device in a communication system for transmitting data in a forward direction from the first device to a second device over parallel data lines of a parallel interface, and transmitting data in a reverse direction from the second device to the first device over the parallel data lines, the method comprising:
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writing specific data to a data register provided in the first device, which outputs data written during forward direction transmission as parallel signals to the parallel data lines, reading contents of the data register, and comparing the written specific data with the read contents to determine whether the read contents and the written data are different, if the read contents and the written data are determined to be different, recognizing that bidirectional communication of the first device and the second device at a predetermined system over the parallel data lines is possible without operator intervention, if the read contents and the written data are determined to be identical recognizing that the bidirectional communication is not possible without operator intervention, and when the read contents and the written data are determined to be different, sending a data transmission request and a notification indicating that data line reverse direction transmission is possible from said first device to said second device. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 30, 31)
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15. A bidirectional communication recognition device in a communication system for transmitting data in a forward direction from a first device to a second device over parallel data lines of a parallel interface, writing data to a data register provided at the first device, and outputting the data as parallel signals to the parallel data lines, the bidirectional communication recognition device comprising:
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reverse direction transmission setting means that sets a data line reverse direction transmission for transmitting data from the second device to the first device over the parallel data lines, data register write/read means that writes specific data to the data register and reads contents of the data register after the data line reverse direction transmission has been set by the reverse direction transmission setting means, comparing means that compares two values including a value of specific data written by the data register write/read and a value of the contents read by the data register write/read means, and determines whether or not the two values are identical, recognition means that recognizes that bidirectional communication over the parallel data lines between the first device and the second device is possible if the comparing means determines that the two values are different without operator intervention, and recognizes that the bidirectional communication over the parallel data lines between the first device and the second device is not possible if the comparing means determines that the two values are identical without operator intervention and notifying means that sends a notification indicating that data line reverse direction transmission is possible from said first device to said second device when said comparing means determines that the data line reverse direction transmission is not possible has been returned from the second device over control lines of the parallel interface. - View Dependent Claims (16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29)
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Specification