Electrical computers and digital data processing systems: input/ – Intrasystem connection – Bus access regulation
Reexamination Certificate
1998-02-17
2001-10-02
Wiley, David (Department: 2155)
Electrical computers and digital data processing systems: input/
Intrasystem connection
Bus access regulation
C710S120000
Reexamination Certificate
active
06298405
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a data communication system, a printing system and a data communication apparatus, and in particular to a system in which data are exchanged among apparatuses.
2 Related Background Art
The most frequently employed peripheral devices for personal computers are hard disks and printers. For data communication, these peripheral devices are connected to personal computers by a digital interface (hereinafter referred to as a digital I/F) such as a SCSI IF, which is a typical, general-purpose interface for small computers.
Digital cameras and digital video cameras are also types of peripheral devices used as input means for personal computers (hereinafter referred to as PCs). As the technique has been developed, static pictures and animated pictures acquired by a digital camera or a video camera are fetched to a PC for storage on a hard disk, or are edited by using a PC and are printed on a color printer, and users for the digital cameras are increased.
The image data are transmitted, via the above described SCSI IF, from a PC to a printer or to a hard disk. In order to transmit such a large quantity of image data, a general-purpose digital I/F having a high data transfer rate is required.
As is described above, conventionally, peripheral devices are connected to a host PC, and image data obtained by a camera are printed by routing them through the PC.
FIG. 3
is a block diagram illustrating an example general interface for a PC. A digital camera
31
is connected to a personal computer (PC)
32
by using a digital I/F, and a printer
33
is connected via a SCSI IF.
In
FIG. 3
, the digital camera
31
comprises: a memory
34
, used as a storage unit; an image data decoder
35
; an image processing unit
36
; a D/A converter
37
; a EVF
38
as a display unit; and a digital I/O unit
39
.
The PC
32
comprises a digital I/O unit
40
, for interfacing the PC
32
with the digital camera
31
; an operating unit
41
, such as a keyboard or a mouse; an image data decoder
42
; a display
43
; a hard disk
44
; a memory
45
, such as a RAM; an MPU
46
, used as a processing unit; a PCI bus
47
; and a SCSI interface (board)
48
, used as a digital I/F. The PC
32
is connected to the printer
33
via the SCSI I/F
48
.
The printer
33
comprises: a SCSI interface (I/F)
49
, connected to the PC
32
by a SCSI cable; a memory
50
; a printer head
51
; a printer controller
52
; and a driver
53
.
With this arrangement, a video signal (image data) obtained by the digital camera
31
is transmitted to the PC
32
. The image data are edited by the PC
32
and the edited data are output to the printer
33
. When the image data stored in the memory
34
of the digital camera
31
are read, they are decoded by the decoder
35
, and the resultant data are processed by the image processing unit
36
for display on the EVF
38
. The data are then routed through the D/A converter
37
and displayed on the EVF
38
. The image data from the memory
34
are transmitted via a cable from the digital I/O unit
39
to the digital I/O unit
40
in the PC
32
.
In the PC
32
, the image data received from the digital I/O unit
40
are stored on the hard disk
44
via the PCI bus
47
, which is an inter-transmission bus, or are decoded by the decoder
42
and the decoded data are stored in the memory
45
or presented on the display
43
. To print the image data, the data are transmitted from the SCSI interface board
48
of the PC
32
along the SCSI cable to the printer
33
. The printer
33
receives the image data at the SCSI interface
49
, and stores them in the memory
50
. Thereafter, the print controller
52
reads the print image data from the memory
50
and outputs them to the driver
53
, and images based on the print image data are printed by the printer head
51
.
As is described above, conventionally the peripheral devices are connected to the host PC
32
, and data are exchanged between the peripheral devices via the PC
32
.
However, among the SCSI IF used in the prior art, some have low data transfer rates or require thick cables for parallel communication, and the types and numbers of peripheral devices that can be connected to these IFs, and the connection systems, are limited. In addition, the inconvenience in many aspects is pointed out.
Many common home PCs have connectors on the rear face for connecting the attachment of SCSI and other cables, and the shape and size of the SCSI connector are such that its insertion and removal are not easy. A mobile or portable device, such as a digital camera or a video camera, which is not normally installed, must also be connected to the connector on the rear of the PC, and this is very difficult.
Usually, many peripheral devices are connected to a personal computer. As the types of peripheral devices have increased, and as I/Fs have been developed, in addition to the PC peripheral devices, many digital apparatuses can be connected across a communication network. While for data communication this is very convenient, a very large amount of data are also frequently communicated between specific devices, which will cause a heavy traffic in the network and adversely effect the communication between other devices in the network. For example, if a user desires sequential or rapid image printing, communication between devices that a user is not aware of may affect the whole network of a host PC during the data communication between the PC and a printer, so that image printing can not be normally performed, or is delayed. As is described above, there is also a load imposed on a PC due to the heavy traffic on a network, or a defect of print data communication due to the operating state of the PC.
SUMMARY OF THE INVENTION
To resolve the above shortcomings, it is one object of the present invention to provide a data communication method and apparatus wherein data can be effectively exchanged between a first node and a second node that are directly connected together, and a communication system including such an apparatus.
It is another object of the present invention to provide a data communication method and apparatus that inhibits entry of a predetermined instruction for a first node during the transmission of data by the first node to a second node, and thus prevents the occurrence of errors during data transmission.
To achieve the above objects, according to the present invention a data communication system comprises a first node and a second node that exchange data, the first node including:
instruction entry means manipulated by a user to enter an instruction,
transmission means for transmitting pertinent data in response to a data request from the second node, and
control means for, during data transmission by the transmission means, inhibiting entry of predetermined instructions at the instruction entry means and providing a predetermined display for the user; and the second node including:
request means for transmitting to the first node a request for the supply of data; and
output means for receiving data from the first node in response to the request submitted by the requesting means and for outputting the data.
It is an additional object of the present invention to employ a general-purpose digital I/F (e.g., IEEE 1394-1995 high performance serial bus), which eliminates as much as possible the problems of the conventional digital I/F and which is mounted as standard in each digital device, so that with this digital I/F, data communication on a network, across which a PC, a printer and other peripheral device, and a digital camera or a camera incorporated digital VTR are connected, is implemented. Also implemented is so-called direct printing, in which image data are directly transferred from a digital camera, or a camera incorporated digital VTR, to a printer and are printed.
It is a further object of the present invention to perform arbitration for the operation of a printer and an operating unit in a camera.
Other objects and features of the present invention
Ito Masamichi
Takahashi Koji
Canon Kabushiki Kaisha
Fitzpatrick ,Cella, Harper & Scinto
Wiley David
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