JPH0787520B2 - Image signal transmitter - Google Patents

Description

TECHNICAL FIELD The present invention relates to an image signal transmitting apparatus for transmitting an image signal.

(Prior Art) Normally, when transmitting a manual call by telephone, an image signal transmitting device such as a facsimile machine may not communicate when the other party is communicating or the operator hears a busy tone when the line is full. Had confirmed.

However, in recent years, it has become possible to automatically make a call by time-specified communication or by using the one-touch key without turning off the handset. For this reason, the operator cannot confirm the busy tone, and the device determines from the called station by the called station identification signal indicating that the called station is a facsimile device.
It was judged that the line was busy when the called station identification signal could not be detected after a considerably long time (for example, 35 seconds).

Further, there is also one that uses a modulation / demodulation circuit to determine whether or not the response signal returned from the line after the dial signal is transmitted is a busy tone.

However, conventionally, even if the communication partner opens the line during the transmission of the image signal, it cannot be detected until the transmission of the predetermined image signal is completed. Therefore, there is a problem that useless image signal transmission is continued and it takes time to execute the next transmission operation.

(Object) An object of the present invention is to provide an image signal transmission device which solves the above-mentioned drawbacks of the prior art. The feature thereof is that busy signal is detected at the interrupt input terminal of the line switching means and the control means for controlling the image transmission means. The detection output of the means is input, and the line switching means is controlled so that the telephone line is opened when the busy tone is detected even during the image transmission.

(Example) Hereinafter, this example will be described with reference to the drawings.

FIG. 1 shows a block diagram of the facsimile machine of this embodiment.

In the figure, reference numeral 2 is a network control unit (hereinafter referred to as NCU) that switches and connects the telephone line 2a to the telephone 4 or the hybrid circuit 6 and holds a DC loop, and 8 reads a document and outputs a binarized image signal. A reading circuit, 10 is an AM-PM-VSB modulator, 12 is a tonal signal sending circuit, 14 is an adding circuit, 16 is a busy tone detecting circuit for detecting a busy tone of the line, and 18 is a tonal signal detecting circuit, and various frequencies are provided. Detect the signal.

Reference numeral 20 is an AM-PM-VSB demodulator, 22 is a recording circuit for sequentially recording demodulated data on recording paper, and 24 is a control circuit for controlling the entire system, which is composed of a CPU, ROM, RAM and the like.

The detection output of the busy sound detection circuit 16 is input to the interrupt input terminal of the control circuit 24, and the busy sound is constantly monitored when the interrupt is enabled.

The operation of the facsimile machine of this embodiment will be described below with reference to the control flow chart (FIG. 2) of the control circuit 24.
The main flow chart is shown in Fig. 2 (a), and Fig. 2 (b).
It shows an interrupt routine when an interrupt occurs.

In step S32, the telephone line 2a is connected to the telephone 4 by the NCU2.
Connected to. Also, other circuits are initialized.
When operations such as transmission, reception, call origination, and call reception are performed in step S34, the telephone line 2a is connected to the hybrid circuit 6 by the NCU 2 and the interruption from the busy tone detection circuit 16 is permitted in step S36.

First, the case where no interrupt occurs will be described.

The pre-procedure is executed in step S38. The pre-procedure includes transmitting a tonal signal (performing control of the signal lines 24d and 24e), transmitting a phase signal (performing control of the signal line 24c), receiving a tonal signal (performing input of the signal line 18), Phase signal reception (performed by inputting signal line 20a)
By.

In step S40, image transmission is executed. Image transmission
It is performed by transmitting an image signal (performed by controlling the signal line 24b) or receiving an image signal (performed by controlling the signal line 24f).

In step S42, the post procedure is executed. The post-procedure is performed by transmitting a tonal signal (performed by controlling the signal lines 24d and 24e) and receiving a tonal signal (performed by inputting the signal line 18a).

In step S44, the telephone line 2a is connected to the telephone 4 side. That is, the signal of the signal level "φ" is output to the signal line 24a. Then, the interrupt input from the busy sound detecting circuit 16 is enabled, and the operation is ended in step S46.

FIG. 2B shows the interrupt processing.

In step S50, it is judged whether or not the busy sound is surely detected. That is, if the signal line 16a remains at the signal level "1", the process proceeds to step S54. On the other hand, the busy tone is not detected. That is, when the signal line 16 is at the signal level "φ", it is determined that a good interrupt is applied to noise or the like, the process proceeds to step S52, and the interrupt returns to the main routine.

In step S54, the telephone line 2a is connected to the telephone 4 side, the signal of the signal level "φ" is output to the signal line 24a, the line is opened, and the process returns to step S46 to end the operation.

In this way, the busy tone is always detected during communication operations such as transmission or reception, so if the other party disconnects the line during communication, or if the line is busy during calling, promptly The communication operation of the device can be ended.

Further, when the line is opened, a busy sound may be displayed or recorded to indicate that the line has been opened.

(Effect) As described above, according to the present invention, the reception signal and the transmission signal are separated by the hybrid means, the busy sound detection output is input to the interrupt input terminal of the control means, and the pre-procedure signal is not transmitted. Even if the receiving side opens the telephone line during the transmission of the image signal and the procedure signal, the telephone line is immediately opened and the next operation is promptly performed by permitting the interrupt until after the transmission of the post-procedure signal. It becomes possible to move to
If the busy sound detection output is interrupted, the telephone line is opened after confirming that there is no change in the busy sound detection output, so it is possible to prevent malfunction due to noise.

[Brief description of drawings]

FIG. 1 is a block diagram of the facsimile machine of this embodiment,
2A and 2B are flow charts of control of the control circuit 24 in FIG. In the figure, 2 is an NCU, 4 is a telephone, 6 is a hybrid circuit, 8 is a reading circuit, 10 is an AM-PM-VSB modulator, 12 is a tonal signal sending circuit, 14 is an adding circuit, 16 is a busy sound detecting circuit, 18 Is a tonal signal detection circuit, 20 is an AM-PM-VSB demodulator, 22 is a recording circuit, and 24 is a control circuit.

Claims (1)

[Claims] 1. A line switching means for capturing and releasing a telephone line, a transmitting means for transmitting an image signal and a procedure signal, a busy sound detecting means for detecting a busy sound, and a telephone captured by the line switching means. While outputting the signal received from the line to the busy tone detecting means,
It has hybrid means for outputting the signal transmitted from the transmitting means to the telephone line, and control means for controlling the line switching means and the transmitting means, wherein the control means is a busy tone of the busy tone detecting means. The detection output is input via an interrupt input terminal, the busy sound detection output is allowed to be interrupted before the transmission of the pre-procedure signal by the transmission means, and the busy sound detection output is transmitted after the transmission of the post-procedure signal by the transmission means. If the busy signal detection output is interrupted during the transmission of the image signal and the procedure signal by the transmitting means, it is confirmed that the busy signal detection output does not change, and the busy signal detection output must not change. An image signal transmitting device, characterized in that the line switching means is controlled by an interruption process so that the telephone line is opened.