Electrical computers and digital processing systems: support – Clock – pulse – or timing signal generation or analysis – Counting – scheduling – or event timing
Reexamination Certificate
1998-11-05
2001-05-22
Lee, Thomas (Department: 2182)
Electrical computers and digital processing systems: support
Clock, pulse, or timing signal generation or analysis
Counting, scheduling, or event timing
C713S320000
Reexamination Certificate
active
06237106
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a communication apparatus and method, and a program in a computer readable medium, and more particularly to technologies of reducing a consumption power of each electronic apparatus for digital data communication or a whole system of electronic apparatuses.
2. Related Background Art
Technologies of configuring one communication system are being developed nowadays. This communication system connects AV apparatuses (e.g., digital cameras, digital video cameras) which process digitalized image signals and audio signals, to personal computers (hereinafter abbreviated as PC) and their peripheral apparatuses (e.g., printers, hard disk drives, CD-ROM drives), by using common communication interfaces, to thereby configure one communication system.
One example of communication interfaces used with such a communication system is IEEE 1394-1995 high performance serial bus standards (hereinafter called IEEE 1394 standards). A communication interface in conformity with IEEE 1394 standards (hereinafter called a 1394 interface) is a digital interface capable of transferring data at higher speed than conventional technologies and supporting a real time transfer of image and audio signals. The 1394 interface has several characteristics as in the following.
(1) The 1394 interface has two transfer modes, an isochronous transfer mode and an asynchronous transfer mode. The isochronous transfer mode ensures transmission/reception of data of a certain amount during each communication period (125 &mgr;s), and is effective for real time transfer of image and audio signals. The asynchronous transfer mode transmits/receives data asynchronously with a communication cycle, and is effective for transmission/reception, when necessary, of control commands, file data, and the like. In each one communication cycle period, the asynchronous transfer mode has a lower priority over the isochronous transfer mode.
(2) The 1394 interface provides a connection configuration with a high degree of freedom. Specifically, a mixture of a daisy chain connection and a node branch connection is possible, allowing a configuration of a network with a high degree of freedom.
(3) The 1394 interface can automatically recognize the connection configuration of a network. Namely, when a new apparatus is added or removed or a power is turned on or off, the new network connection configuration is automatically recognized and IDs assigned to respective apparatuses are automatically set again.
(4) Since data transfer is serially executed between apparatuses, a thin communication cable can be used and a smaller connector can be used. The communication cable has a power feed pair cable so that power can be supplied to a 1394 interface of an apparatus whose main power was turned off. Therefore, even if the main power of an apparatus is turned off, communication over the network cannot be shut down.
The 1394 interface is, however, associated with the following problem.
In order for an apparatus equipped with a 1394 interface to achieve the above-described characteristic features, it is necessary to always feed a power to the whole circuitry of its own 1394 interface. Therefore, even during the period while an apparatus connected to the network is not necessary to communicate with another apparatus, it is required to always feed a power to its own 1394 interface wastefully. This problem becomes conspicuous when a portable apparatus (e.g., digital cameras, camera mounted digital video recorders) driven with an internal power source such as a battery is used. The 1394 interface of this portable apparatus consumes its internal power source more quickly.
SUMMARY OF THE INVENTION
An object of the present invention is to solve the above-described problem.
Another object of the invention is to reduce a power consumption of a communication apparatus and to establish a communication path to another communication apparatus at any time when necessary.
As a preferred embodiment for such objects, a communication apparatus of this invention is disclosed which comprises: communication means having a first mode capable of communicating with an external apparatus and a second mode having a consumption power smaller than the second mode; control means for alternately switching between the first and second modes after the communication apparatus is connected to the external apparatus; and detecting means for detecting the external apparatus as a communication destination during a period of the first mode.
As another embodiment, a communication apparatus of this invention is disclosed which comprises: communication means having a first mode capable of communicating with an external apparatus and a second mode not communicating with the external apparatus; and control means for controlling the communication means so as to alternately switch between the first and second modes, wherein a period of the first mode is longer than a period of the second mode.
As another embodiment, a communication apparatus of this invention is disclosed which comprises: communication means having a first mode capable of communicating with an external apparatus and a second mode not communicating with the external apparatus; and control means for controlling to make a period of the first mode longer than a period of the second mode and to make the period of the first mode overlap the period of the first mode of at least one of external apparatuses.
Another object of the invention is to provide a communication method capable of reducing a power consumption of a communication apparatus and establishing a communication path to another communication apparatus when necessary.
As a preferred embodiment for such an object, a communication method of this invention is disclosed which comprises the steps of: communicating with an external apparatus; controlling to alternately switch between a first mode capable of communicating with the external apparatus and a second mode having a consumption power smaller than the second mode, after a connection to the external apparatus is established; and detecting the external apparatus as a communication destination during a period of the first mode.
As another embodiment, a communication method of this invention is disclosed which comprises the steps of: communicating with an external apparatus; and controlling to alternately switch between a first mode capable of communicating with the external apparatus and a second mode not communicating with the external apparatus, a period of the first mode being longer than a period of the second mode.
As another embodiment, a communication method of this invention is disclosed which comprises the steps of: communicating with an external apparatus; and controlling to make a period of a first mode capable of communicating with the external apparatus longer than a period of a second mode not communicating with the external apparatus and to make the period of the first mode overlap the period of the first mode of at least one of external apparatuses.
Another object of the invention is to provide a program written in a computer readable medium capable of reducing a power consumption of a communication apparatus and establishing a communication path to another communication apparatus when necessary.
As a preferred embodiment for such an object, a program written in a computer readable medium of this invention is disclosed which comprises the steps of: instructing to communicate with an external apparatus; controlling a communication apparatus to alternately switch between a first mode capable of communicating with the external apparatus and a second mode having a consumption power smaller than the second mode, after a connection to the external apparatus is established; and instructing to detect the external apparatus as a communication destination during a period of the first mode.
As an embodiment, a program written in a computer readable medium of this invention is disclosed which comprises the steps of: instructing to communicate
Kobayashi Takashi
Koyama Shinichi
Canon Kabushiki Kaisha
Fitzpatrick ,Cella, Harper & Scinto
Lee Thomas
Patel Nitin
LandOfFree
Communication apparatus and method, and program in computer... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Communication apparatus and method, and program in computer..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Communication apparatus and method, and program in computer... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2533987