JPH0476547B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a facsimile receiver, and particularly to a facsimile receiver having an error correction function.

[Conventional technology]

Conventional facsimile receivers can be activated and automatically receive a call signal from a telephone line with normal transmission quality, and do not have an error correction function when connected to a telephone line.

Furthermore, devices that use a transmission line with poor transmission quality use an error correction function to correct data transmission errors on the transmission line in order to obtain good image quality. in this case,
Since the data format on the transmission path is different from the data format of G3 machines that meet the International Telegraph and Telephone Consultative Committee (hereinafter referred to as CCITT) standard, facsimile receivers equipped with an error correction function cannot communicate with G3 machines that meet the CCITT standard. do not have.

Therefore, a facsimile receiver that can be connected to both a telephone line and a transmission line with low transmission quality, and selects either one for communication, has a signal processing circuit that does not include an error correction circuit, and a signal that includes an error correction circuit. It has a processing circuit, and the user of the receiver must set which circuit to use prior to communication.

[Problem that the invention seeks to solve]

The conventional facsimile receiver described above can be connected to both a telephone line and a transmission line with low transmission quality, and when selecting one of them for reception, a signal processing circuit that does not include an error correction circuit is required prior to reception. Since the user is now able to set which circuit to use, including the error correction circuit and the signal processing circuit, the system automatically receives a call signal from a telephone line or a transmission line with poor transmission quality. It has the disadvantage of not being able to do anything.

An object of the present invention is to provide a facsimile receiver that automatically selects a signal processing circuit corresponding to the transmission quality of the transmission path to receive a calling signal from either a telephone line or a transmission path with low transmission quality. Our goal is to provide the following.

[Means for solving problems]

In the facsimile receiver of the present invention, a first transmission line having normal transmission quality and a second transmission line having transmission quality inferior to that of the first transmission line are connected, and the first
and a paging signal detection circuit that distinguishes and detects paging signals from the second transmission path and outputs a switching signal; and an error correction encoding circuit that corrects data transmission errors in received and demodulated coded data; a switching circuit that excludes the error correction decoding circuit until reception from the first transmission path is completed in response to the switching signal when the calling signal detection circuit detects the calling signal from the first transmission path; It consists of:

〔Example〕

Next, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a block diagram of one embodiment of the present invention.

As shown in FIG. 1, in this embodiment, a telephone line 1 serving as a first transmission line having normal transmission quality and a wireless line 2 serving as a second transmission line having lower transmission quality than the telephone line 1 are connected. Calling signal detection circuit 3
and a demodulation circuit 4 that demodulates the received modulated signal.
Error correction decoding circuit 5 that corrects data transmission errors
, a switching circuit 6 , and a receiving buffer 7 .

In FIG. 1, when a radio paging signal C _R is input via the radio line 2, the paging signal detection circuit 3 detects the radio paging signal C _R ;
A low level switching signal S is output from.

The switching circuit 6 connects the radio line 2 to the modulation circuit 4 and connects the error correction decoding circuit 5 to the receiving buffer 7 in response to the low level switching signal S.

Therefore, a modulated signal input via the radio line 2 is input to the demodulation circuit 4, and data demodulated by the demodulation circuit 4 and subjected to error correction encoding is supplied to the error correction decoding circuit 5. The encoded data whose transmission errors have been corrected by the error correction decoding circuit 5 is received data.
It is supplied to the reception buffer 7 as D _R.

Further, when a telephone ringing signal _CT is input via the telephone line 1, the ringing signal detection circuit 3 detects the telephone ringing signal _CT , and a high level switching signal S is output from the ringing signal detection circuit 3. .

The switching circuit 6 connects the telephone line 1 to the demodulating circuit 4 and connects the output end of the demodulating circuit 4 to the receiving buffer 7 in response to the high level switching signal S.

Therefore, a modulated signal input via the telephone line 1 is input to the demodulation circuit 4, and the encoded data demodulated by the demodulation circuit 4 is supplied as is to the reception buffer 7 as reception data _DR .

In either case, the received data D _O is sent from the reception buffer 7 to a decoding circuit (not shown) and subjected to decompression processing.

〔Effect of the invention〕

As explained above, the facsimile receiver of the present invention distinguishes and detects the calling signals from the first transmission path with normal transmission quality and the second transmission path with inferior transmission quality, and uses the detection results as By automatically selecting the use of the error correction encoding circuit according to the signal processing time, the user can start up and automatically receive the call signal from each transmission path without having to configure the signal processing circuit in advance. The effect of being able to do

[Brief explanation of the drawing]

FIG. 1 is a block diagram of one embodiment of the present invention. DESCRIPTION OF SYMBOLS 1... Telephone line, 2... Wireless line, 3... Calling signal detection circuit, 4... Demodulation circuit, 5... Error correction decoding circuit, 6... Switching circuit, 7... Reception buffer, C _R ... ...radio calling signal, C _T ... telephone calling signal, D _O , D _R ... received data, S ... switching signal.

Claims (1)

[Claims] 1 A first transmission line having normal transmission quality and a second transmission line having lower transmission quality than the first transmission line are connected, and the calling signals from the first and second transmission lines are separately detected. a paging signal detection circuit that outputs a switching signal; an error correction decoding circuit that corrects data transmission errors in coded data received and demodulated; A facsimile receiver comprising: a switching circuit that excludes the error correction decoding circuit until reception from the first transmission path is completed in response to the switching signal when a calling signal is detected.