Telecommunications – Radiotelephone system – Including private cordless extension system
Reexamination Certificate
1998-05-20
2001-01-16
Cumming, William (Department: 2749)
Telecommunications
Radiotelephone system
Including private cordless extension system
C379S100010, C358S442000, C712S001000
Reexamination Certificate
active
06175742
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Technical Field
The present invention relates generally to an image transmission apparatus which establishes facsimile communication with a facsimile machine through a telephone line, and more particularly to an image transmission apparatus which includes a main facsimile unit connected to a telephone line and a sub-facsimile unit communicating with the main unit by radio.
2. Background Art
Japanese Patent First Publication No. 4-115762 teaches, as shown in
FIG. 8
, a conventional facsimile machine which consists of a main unit
100
and a sub-unit
200
. The main unit
100
has a communication controller receiving a telephone signal through a telephone line
350
. The sub-unit
200
has facsimile terminal equipment. The main unit
100
and the sub-unit
200
also have transceivers
112
and
202
, respectively, for radio transmission therebetween. The transceiver
112
transmits facsimile information from a calling party's facsimile machine
300
along with an operating procedure signal to the transceiver
202
. The transceiver
202
of the sub-unit
200
transmits an operating procedure signal to be sent to the facsimile machine
300
to the transceiver
112
of the main unit
100
.
A communication condition between the facsimile machine
300
connected to the main unit
112
through the telephone line
350
and the sub-unit
200
connected to the main unit
100
depends upon a radio transmission condition between the main unit
100
and the sub-unit
200
as well as a telephone communication condition. Thus, even if the telephone communication condition is good, a communication failure may occur or a retry operation may be performed many times as long as the radio communication condition is unstable, thus resulting in an increase in wasteful use of the telephone line.
SUMMARY OF THE INVENTION
It is therefore a principal object of the present invention to avoid the disadvantages of the prior art.
It is another object of the present invention to provide an image transmission apparatus which is designed to establish fine facsimile communication regardless of a radio communication condition between a main unit and a sub-unit for eliminating wasteful use of a telephone line.
According to one aspect of the present invention, there Is provided an image transmission apparatus which comprises a first unit having a facsimile function, a second unit receiving a facsimile signal from a calling party's facsimile machine through a telephone line, a field strength detecting means for detecting a level of field strength of the radio signal transmitted from the first unit to the second unit, and a switching means for switching an operation mode of the second unit. The second unit operates in a radio transmission mode and a facsimile mode. The radio transmission mode is to transmit the received facsimile signal together with an operation procedure signal to the first unit using a radio signal and also transmit an operation procedure signal sent from the first unit using a radio signal to the calling party's facsimile machine through the telephone line for establishing facsimile communication between the calling party's facsimile machine and the first unit. The facsimile mode is to establish facsimile communication with the calling party's facsimile machine instead of the first unit. The switching means switches between the radio transmission mode and the facsimile mode of the second unit according to the level of the field strength detected by the field strength detecting means. Specifically, the switching means controls the second unit so as to operate in the facsimile mode when the level of the field strength becomes smaller than a preselected level.
In the preferred mode of the invention, the second unit includes a memory for storing therein the facsimile signal in the facsimile mode. The second unit transmits the facsimile signal stored in the memory to the first unit after completion of the facsimile communication with the calling party's facsimile machine in the facsimile mode when the field strength detected by the field strength detecting means exceeds the preselected level.
The second unit includes a memory for storing therein all of the facsimile signal transmitted from the calling party's facsimile machine. The second unit may transmit all of the facsimile signal stored in the memory to the first unit after completion of the facsimile communication with the calling party's facsimile machine in the facsimile mode when the field strength detected by the field strength detecting means exceeds the preselected level.
The second unit includes informing means for informing an operator of a failure of radio communication between the first and second units when the radio communication is blocked for a preselected period of time after the field strength detected by the field strength detecting means is decreased below the preselected level.
The first unit includes informing means for informing an operator of a failure of radio communication between the first and second units when the radio communication is blocked for a preselected period of time after the field strength detected by the field strength detecting means is decreased below the preselected level.
The second unit has printing means for printing out the facsimile signal received in the facsimile mode.
The second unit includes a first communication control portion establishing transmission of the operation procedure signals between the second unit and the calling party's facsimile machine, a second communication control portion establishing transmission of the operation procedure signals between the second unit and the first unit, and a monitor portion monitoring an operation procedure signal-transmitted condition between the first unit and the calling party's facsimile machine. When the level of the filed strength of the radio signal detected by the field strength detecting means is greater than the preselected level, the first and second communication control portions establishes communication between the first unit and the calling party's facsimile machine, while when the level of the field strength of the radio signal is smaller than the preselected level, the first communication control portion produces an operation procedure signal corresponding to an operation procedure signal to be produced by the first unit and transmits the same to the calling party's facsimile machine.
According to another aspect of the present invention, there is provided an image transmission apparatus which comprises a main unit provided to be connected to a telephone line, a sub-unit performing a facsimile operation, a radio communication establishing means for establishing radio communication between the main unit and the sub-unit to transfer facsimile image information and an operation procedure signal using a radio signal, a field strength detecting means for detecting a field strength of the radio signal, and a partially processing means for partially processing the facsimile image information according to the field strength detected by the field strength detecting means.
In the preferred mode of the invention, a transmission image density control means is further provided for controlling the partially processing means to adjust the density of a facsimile image provided by the facsimile image information transmitted from the main unit to the sub-unit according to the field strength detected by the field strength detecting means and an image-reading density signal provided by the calling party's facsimile machine.
The image transmission apparatus further includes an image reading unit mounted in the sub-unit for reading a facsimile image of a document, an image-reading density selecting means for selecting between a higher density mode and a lower density mode, a transmission image density control means for controlling the partially processing means to adjust the density of the facsimile image read by the image reading unit to be transmitted to the ma
Hashibe Yukari
Moteki Masayuki
Cumming William
Matsushita Graphic Communications Systems Inc.
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