DE2905982A1 - FACSIMILE RECIPIENT WITH MULTIPLE ACCESS - Google Patents

Description

FACSIMILE RECEIVER WITH MULTIPLE ACCESS

The invention belongs to the field of facsimile signal transmissions. In particular, it relates to a facsimile receiver to which a plurality of telephone lines are assigned and to which can receive multiple facsimile messages at the same time, each to be output in the form of a document. Man standardizes such systems for facsimile recipients with multiple access.

The invention is a facsimile receiver with Multiple access based on η assigned telephone lines, where η is at least 2 and the recipient is a printing device for printing copies of a document based on received Having facsimile signals, characterized in that this printing device is based on the reproduction of the various documents of facsimile signals received on different lines and that η line circuits, each one Line terminal, a demodulator and control logic for monitoring the reception of the telephone line in question Containing incoming facsimile signals, and a memory are provided, the capacity of which is greater than the content of a reproduced Document is and the one the demodulator of each of the η line circuits for registering the connected by the various Lines coming facsimile signals with the memory connecting access control circuit with η inputs and an output and a write-read control circuit for filling and emptying associated with the successive addresses for filling

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of the memory in time with the access from the telephone lines s control circuit received and the successive addresses for emptying the memory for reproducing the one document corresponding registered signals determined in the printing device.

The invention is described below using an exemplary embodiment with reference to the single figure enclosed explained in more detail.

Several telephone lines, here n = 3, labeled 1, 2 and 3, are associated with a facsimile receiver. This recipient has a document printing device 5 based on his Received facsimile signals input the copy of a document generated. In addition, the receiver includes η circuit circles, with 7, 8 and 9, each of which connects the circuitry of the receiver to a telephone line. Every management group contains a line terminal 10, a control logic IL connected to the terminal 10 and a demodulator 12, which by the logic circuit II is controlled and with the telephone line concerned via the line terminal 10 is in communication. The line terminal 10 adapts the facsimile receiver in terms of the Potentials and its impedance to the telephone line and ensures the galvanic separation between the telephone line and the Facsimile receiver circuitry. The circuit 10 is a known and standardized interface module. The control logic Il detects the ringing signals coming from the assigned telephone line. It allows the exchange of information between Facsimile receiver and the calling party prior to receiving any facsimile signals from the telephone line to the

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Determine and establish the operational readiness of the receiver. The demodulator 12 then receives the signals coming from the telephone line and demodulates them.

The other management circuits 8 and 9 correspond to management circuit 7.

The output of the demodulator 12 of each of the line circuits 7, S and 9 leads via an access control circuit 16 to a memory

15. This access control circuit 16 is a circuit with η inputs and a single output connected to the input of memory 15. He plays the role of the multiplexing circuit for the demodulated signals to be introduced into the memory. The access control circuit 16 is by itself a write-read control circuit 17 is controlled, which manages the memory content. This control circuit 17 is this to each of the Line circuits 7 to 9 connected and receives from the line circuits the determination of the telephone lines assigned to them incoming call signals and allows or denies the connection of one of the lines to the receiver depending on the willingness to store the received signals. These Functions are indicated by a Zv / eirrichtung connection between the control circuit 17 and each of the line circuits 7 to 9. The read-write control circuit 17 also determines depending on the predetermined bit frequency on each telephone line, for example 2400 bits per second, and depending on the number connected to the receiver Lines the number of signals to be received in the memory 15 and consequently supplies it to the access control circuit

16, to which it is connected, the one for the lines

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received and stored signals suitable multiplex clock. At the same time, the read / write control circuit 17 supplies the memory with the successive addresses for storage of incoming signals according to the number of incoming signals.

The manner in which the signals given to the input of the memory are stored is controlled by the control circuit 17 certainly. The storage of the signals coming from a telephone line can be specified in a sequence of addresses Area are carried out by the control circuit 17 coming from the telephone line connected at the time Is assigned to signals. Advantageously, the facsimile signals transmitted in compressed form on the various telephone lines. In the memory 15 they are also grounded in the compressed Form saved. The output of the memory 15 is assigned to the printing device via two output registers 21 and 22 Decoder 20 connected.

The task of the decoder 20 is to convert the signals present in compressed form in the memory into others, directly signals that can be evaluated in the printing device 5. So if the compression of the signals transmitted over the telephone lines in a coding the lengths of zones with the same degree of blackening of the analysis signals of the original document and / or in another coding exists, the reverse conversion is carried out by the decoder to that in the analysis of the original document to recover generated signals that are identical to signals. For this decoding of the signals registered in the memory "calls"

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the decoder to restore each corresponding document the signals registered in the memory 15, while the control circuit 17, which is also connected to the decoder, the successive output addresses of the memory with the request speed of the decoder to restore the registered signals corresponding to a document are determined. The memory is therefore also matched by the decoder supplied variable speed and emptied under the supervision of the circuit 17 which provides the addresses for this emptying indicates.

With the aid of the two registers 21 and 22, the signals coming from the decoder 20 can be read at the restoration speed of the document can be output by the printing device 5. These two registers are chosen so that their capacity corresponds to the content of a document rope, i.e. the Λη number of. 'scanning points per line of the document. The two registers 20 and 21 are alternately switched to the filling position by the decoder. By a counter 23 they are at alternately with each pass through a given counting state corresponding to the number of scanning points per line of the document switched to the emptying state. The named counter 23 is for this purpose by a counter not shown here Clock is applied, which belongs to the printing device, with signals HI supply the scanning speed of the successive scanning points of a line of the document. So becomes one of the registers and 22 with variable speed from the decoder filled, while the other register with constant, from the printing device 5 is emptied at a certain speed.

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With the facsimile receiver according to the invention, facsimile signals arriving from a plurality of subscribers can thus be received at the same time The documents corresponding to them are then received one after the other by a single high-speed printing device can be printed out. The memory 15 therefore temporarily stores the incoming calls from different telephone lines Facsimile signals by, while the associated control circuit 17 the order of these signals to be established Documents determined.

The storage capacity of the memory 15 depends on the memory chosen by the number of accesses of the receiver, the capacity not being exactly proportional to this number have to be. For example, if the content of a document is in

5 5
compressed form is about 10 to 4.10 bits, a memory with a capacity of about 5.10 bits is chosen if the receiver according to the prior art has only a single access or a single telephone line, this capacity being, for example, 4.10 bits for reception of the document just transmitted and to 10 bits for the beginning of the reception of the following document to be transmitted while the printout pha.sa of the document already transmitted is divided. In contrast, in a receiver with multiple access according to the invention, the capacity of the memory can be limited to 7.5.10 bits if the receiver has two accesses, and to 10 bits for a receiver with three accesses. This possibility of using a memory with a capacity that is not proportional to the number of accesses is explained on the one hand by the fact that the transferred documents only have full capacity in exceptional cases

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require and on the other hand by the fact that the reading time of the stored, signals corresponding to a Dolcument transmitted by the duration of the printout is determined (about 20 seconds for a xerographic printer), significantly below that for writing in the corresponding to the content of a transmitted signal Signals in the memory required duration; this writing time depends on the bit length of the transmitted document and on the transmission power of the telephone line or the processing ability of the demodulator and is about one minute if a modem with 4800 bits oro second is used.

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Claims (1)

Fo ii 157 D Feb 16, 1979 COI-IP & GNIH lUDUSTSIELLE DES TELECOMMUNICATIOHS C IT-ALCATEL SA
• I, rue de la Baume, 75008 PARIS, France FAKSIHILE EMPFILHGER WITH MULTIPLE ACCESS PATENT CLAIMS Facsimile receiver with multiple access based on η him succeedsGn telephone lines, where η is at least equal to 2 and the receiver is a printing device for printing out copies of a document on the basis of received facsimile signals having, characterized in that this printing device (5) for reproducing the various documents based on facsimile signals received on different lines is formed and that η line circles (7,0,9), the in each case a line terminal (10), a demodulator (12) and a control logic (11) for monitoring the reception of the the relevant telephone line (1,2,3) incoming facsimile signals included, and a memory (15) are provided, the capacity of which is greater than the content of a document to be reproduced is and de ;: a demodulator (12) of each of the η line circuits (7,8 ^ 9) for registering the connected by the various Lines coming facsimile signals with the memory (15) connecting access control circuit (16) with η inputs and one Output and a read-write control circuit (17) for filling and emptying is assigned to the successive addresses 909835/0644 for filling the memory (15) in time with that of the telephone lines received by the access control circuit (16) and the successive addresses for emptying the memory (15) playback of the registered signals corresponding to a document determined in the pressure device (5). 2 - facsimile receiver according to claim 1, wherein the of the Lines received facsimile signals are in compressed form, characterized in that the facsimile signals received from the connected lines are registered in compressed form in the memory (15) and that the receiver also has a decoding circuit (2O) connected to the memory (15) and the read / write control circuit (17) that from the variable speed memory of the decoder receives signals. and two output registers (21,22) alternately loads, which alternately interrogated by the pressure device at a constant transfer rate will. 3 - Receiver according to one of claims 1 and 2, characterized in that the capacity des, memory (15) is chosen so that it has fewer than η documents able to store at the same time. 909835/0644