IE48086B1

IE48086B1 - A centralised transmission facsimile installation

Info

Publication number: IE48086B1
Application number: IE544/79A
Authority: IE
Original assignee: Cit Alcatel
Priority date: 1978-02-23
Filing date: 1979-08-08
Publication date: 1984-09-19
Also published as: NL7901382A; JPS54118122A; GB2015304A; DE2906073A1; LU80943A1; DE2906073B2; CA1119711A; DE2906073C3; IE790544L; FR2418588A1; GB2015304B; FR2418588B1; IT1118407B; IT7967399A0; BE873983A

Abstract

A facsimile transmitter/receiver includes a document analyser (1), and a document printer (3). It may also include bulk memory (2) which can act either as a further source or as a further destination. The transmitter/receiver is interfaced with a plurality n telephone lines (4, 5, 6) by means of n line circuits (7, 8, 9) each of which includes a line connector circuit 10, a modem 11 and a small amount of memory (25) (say sufficient for one scan line of a document), and a plurality p of temporary memories (15, 16, 17, 18) each of which has storage for facsimile signals corresponding to a complete page of a document. p is greater than n. Each of the temporary memories can be connected via a link selector (21) to any of the facsimile signal sources or destinations or to any of the telephone lines via a time-shared codec (22) which performs translation between "raw" facsimile signals and a less redundant form of signal suitable for transmission. Independent reading and writing helps isolate source(s) and destination(s) from slower transmission and connection delays inherent to telephone lines.

Description

A CENTRALISED TRANSMISSION FACSIMILE INSTALLATION The present invention relates to facsimile signal transmission installations of the type that operate as transmitter-receivers of facsimile signals.

The aim of the present invention is to provide for simultaneous transmission or reception of the contents of a plurality of documents using a known type of facsimile signal transmission installation capable of operating as a transmitter-receiver of facsimile signals.

The present invention provides a facsimile instal10 lation comprising : facsimile signal input means which include a document analyser; facsimile signal output means which include a document printer; and centralised transmission means for providing communication between a plurality, n , telephone lines and the said facsimile signal input and output means; wherein the centralised transmission means comprises :a plurality, £, temporary memories each having a storage capacity sufficient to store signals corresponding to one page of a document ; n and £ being integers with £ greater than n ; n line circuits for connection to respective telephone lines for two-way distant transmission of signals over the telephone lines; each line circuit comprising a modulatordemodulator (modem) and a line connector circuit ; connection means for connecting the temporary memories to receive data from the said facsimile signal input means or· from the line circuits, and for connecting the temporary memories to deliver data to the said facsimile signal output means or to the line circuits; and a control unit responsive to the line circuits, to the facsimile signal input and output means, and to the state of each of the £ temporary memories, to control the temporary memories and the connection means in such a manner that at any one time each temporary memory which is in use at that time for receiving or for delivering data is connected to equipment on one only of its sides, i.e. equipment on its line circuit side only or to equipment on its facsimile signal input and output means side only.

A facsimile installation having centralised transmission and embodying the invention is described by way of example with reference to the sole figure of the accompanying drawing which is a block diagram of the installation.

The installation for centralised transmission of facsimile signals shown in the figure comprises facsimile signal input means and facsimile signal output means. The facsimile signal input means include a document signal analyser circuit 1 and a circuit 2 which provides direct access to facsimile signals, e.g. to a ccmputer or to a memory such as a disc. The facsimile signal output means include a document printer circuit 3 and a circuit (in this case the circuit 2) providing a direct output for facsimile signals, for example the computer mentioned above or a memory such as a disc, n telephone lines (in this case 3 , i.e. n = 3)and referenced 4, 5 and 6 are assigned to the installation. The installation includes n line circuits 7,8 and 9, each connected to a respective one of the telephone lines. Each of the line circuits enables distant two-way transmission for sending facsimile signals from the input means (1,2) down the telephone line and for receiving signals from the telephone line which become the facsimile signals that are applied to the output means (3,2). Each line circuit, e.g. the circuit 9, includes a line connector circuit 10 which provides DC and impedance matching between the facsimile signal transmission installation and its telephone line. Such a connector circuit 10 is of known type and is provided to meet the standards laid down by each country for connecting a facsimile receiver to a telephone line. Xt switches between the function of sending signals to the telephone line and the function of receiving signals from the line, and it ensures isolation of the metallic path between the line and the circuits of the facsimile transmission installation. In the line circuit 9, as in each of the other line circuits, the line connector circuit is connected to a modulator-demodulator 11 which is thus put in communication with the telephone line via the line connector circuit. £ temporary memories referenced 15,16,17 and 18, where £ is an integer greater than n ( and in this case p = 4),are used in the facsimile signal transmission installation for temproary storage of facsimile signals delivered from the input means (1,2) and of facsimile signals coming from the line circuits 7 to 9 from the telephone lines 4 to 6. These memories are also used to enable deferred application of the stored facsimile signals to the outputs means (3,2) and to the line circuits 7 to 9. Each of the £ memories is chosen to have a capacity equal to 1 page of a document i.e. to the number scan points which constitute an entire page of the document during document analysis or during document reproduction.

Documents to be sent, whether from analysis in the circuit 1 or from the direct access to facsimile signals of the circuit 2, preferably include a head-code or are preceded by code signals for indicating in particular the destination of the document, e.g. the telephone number to which it is to be sent, and references of the document in order to provide for automatic addressing of the document to the addressee.

The £ temporary memories 15 to 18 are connected via a signal transfer bus 20 ( shown in the form of a double link providing signal transfer in one or other direction) to a link selector 21 for linking each of the £ memories to the input means (1,2) and to the output means (3,2) for facsimile signals. The link selector 21 is neither illustrated in detail nor described in detail. Together with the link bus, it enables writing into any one of £ memories when in a write mode for temproary storage of facsimile signals delivered by the analyser circuit 1 or by the circuit 2; also, together with the link bus it enables reading from any one of the £ memories when in a read state, by the printer circuit 3 or by the circuit 2. The selector is an electronic selector and can be easily realised by the man in the art in such a manner that the memories are linked independently from each other with the circuits of the input or output means. However, any one memory will only be linked with a single circuit of the input and output means for facsimile signals during writing or reading, as the case may be.

In the drawing, a coder-decoder 22 (codec) is inserted 2 temporary memories 15 to 18 and n line circuits 7 to 9.

The £ temporary memories are connected via a signal transfer bus 23 ( shown in the form of a two-way link insuring signal transfer in one direction or the other) to the codec 22 which is itself connected to each of the line circuits 7 to 9. The codec 22 is of known type and is intended to reduce redundancy in the signals received from the temporary memories before sending them over one or other of telephone lines 4 to 6, or to perform the inverse transformation on the signals received from the line circuits 7 to 9 before storing them in one or other of the temporary memories. It operates for example, when encoding by detecting run-lengths and encoding these run-lengths. Each of £ temporary memories 15 to 18 may thus be written to or read from at a variable speed when it is put into communication with one of the line circuits 7 to 9 via the codec.

The codec 22 will be advantageously used both during coding and during decoding on a time-sharing basis. For this purpose, an address bus 24 is provided between the codec 22 and the £ temporary memories 15 to 18 to enable each of the addressed memories to be put into read mode or write mode.

In each of the line circuit 7 to 9 there is a circuit constituted by an auxiliary memory such as the memory 25 in the line circuit 9 which is associated with the time-shared codec 22. The auxiliary memories such as the memory 25 are each of small capacity, e.g. corresponding to the number of scan points along a line of a document. Each of the auxiliary memories is controlled for reading or writing from the codec to enable the transfer of coded signals towards the appropriate auxiliary memory or the transfer of signals to be decoded taken from the appropriate auxiliary memory. In the drawing a single link is shown between each of the line circuits 7 to 9 or its auxiliary memory and the codec 22 to enable addressing of the required auxiliary memory by the codec and to enable the transfer of coded signals or signals to be decoded between the said auxiliary memory and the codec. Each of the auxiliary memories such as 25 is connected to the modem of its line circuit.

Finally, the installation has a control unit 30 for controlling the circuits of the installation, and to provide dynamic supervision of the signals stored in the £ temporary msnories as a function of the occupancy of the telephone lines. This control unit tests the state of the various circuits of the installation. In particular, it tests the state of the temporary memories 15 to 18 before authorising any document analysis or any other facsimile signal input from the circuit 2 and to authorise any connection of the installation to a telephone line to send signals via the codec operating as a coder or to receive signals using the codec as a decoder.

The control unit also authorises printing of a document by a printer circuit and/or the output of facsimile signals towards the circuit 2 as soon as these circuits are free and the contents of one or two of the temporary memories is waiting therefor. These various functions of the control circuit 30 are illustrated by two-way connections between the control circuit 30 and the other circuits concerned in the installation. This control unit thus supervises the waiting list of documents whose respective contents are stored in the temporary memories as a function of the traffic on the telephone lines assigned to the installation. The operation of the installation and the various functions of its control unit 30 will appear more clearly below when the process of sending the contents of a document to line or receiving signals for document reproduction are examined. When an operator makes a request for document analysis, which request is transmitted frcm the document analyser circuit 1 to the control unit 30, the unit 30 checks whether one of the £ tanporary msnories 15 to 18 is free, i.e. empty of useful information. If the £ msnories are full the control unit prohibits document analysis and the operator must wait. If the control unit 30 detects that one of the tanporary msnories is free, it authorises document analysis by the circuit 1: the document is analysed at high speed and its contents, including the head-code giving the destination and reference code signals of the document, is stored in the temporary memory. As soon as one of the lines is free, and provided that the installation is not operating as a signal receiver on another line, the destination code signals enable the addressee to be addressed and the contents of the temporary memory is sent to the line using the codec as a coder and the modem of the corresponding line circuit as a modulator. For simultaneous sending of the contents of several temporary memories over as many telephone lines, the codec encodes the contents of these temporary memories on a time-shared basis. As soon as the entire contents of one of the memories is sent to line, the line in question is released and the temporary memory is considered as being available for further storage.

If the called party or the addressee of the contents the document stored for sending is not available, the contents of the document waits in the temporary memory for a new sending attempt at a later moment. The contents of the memory in question will be rejected after a more or less long wait and will be dumped after a defined number of attempts at sending: an auxiliary printer, referenced 31 in the drawing, and controlled by the unit 30 gives the references of the document whose contents has not been transmitted to its destination.

When a call is received in the line connector circuit of the line in question, it is transmitted to the control unit 30 which tests the state of the temporary memories. If none of the temporary memories is free or if the installation is sending, the control unit transmits a command to the line circuit to prohibit reception, which is translated into a busy signal which is returned to the calling party. If a temporary memory is detected in the free state and if the installation is not sending, the signal sent over the line by the calling party may be received: then, by using the modem of the corresponding line circuit as a demodulator and by using the codec as a decoder, the signal is stored in the free temporary memory. To receive signals from a plurality of lines simultaneously and to store them in as many temporary memories, the codec may operate on a time-sharing basis.

The reproduction of a document whose contents is now stored in the temporary memory is performed by the printer circuit 3 as soon as the control unit 30 detects that the printer is available.

Such a facsimile transmission installation operates automatically as a facsimile sender and as a facsimile receiver, it analyses documents or receives facsimile signals direct for sending to line independently of their line transmission, and it receives signals from a line independently of their reproduction as a document or of their onward transmission to other circuits. Thus, the operator of such an installation is kept busy only for the minimum of time required for the analysis of each document, while the control unit 30 provides dynamic supervison of the circuits of the installation for sending the contents of analysed documents to line and for receiving signals from the lines and reproducing the corresponding documents. This installation also makes it possible to send the contents of several documents simultaneously to their respective addressees from a single document analyser circuit; it also makes it possible to receive several signals simultaneously from different callers and to reproduce these documents later on a single printer circuit.

The present invention has been described vzith reference to an embodiment illustrated in the accompanying drawing ; naturally without going beyond the scope of the invention it is possible to add detail modifications thereto and/or to replace various means by others which are technically equivalent.

Claims

1./ A facsimile installation comprising : facsimile signal input means which include a document analyser; facsimile signal output means which include a document printer; and centralised transmission means for providing communication between a 5 plurality, η , telephone lines and the said facsimile signal input and output means; wherein the centralised transmission means comprises:a plurality, £ , temporary memories each having a storage capacity sufficient to store signals corresponding to 10 one page of a document; n and being integers with £ greater than n ; n line circuits for connection to respective telephone lines for two-way distant transmission of signals over the telephone lines, each line circuit compromising a 15 modulator-demodulator (modem) and a line connector circuit ; connection means for connecting the temporary memories to receive data from the said facsimile signal input means or from the line circuits, and for connecting the temporary memories to deliver data to the said facsimile signal 20 output means or to the line circuits : and a control unit responsive to the line circuits, to the facsimile signal input and output means, and to the state of each of the £ temporary memories, to control the temporary memories and the connection means in such a manner 25 that at any one time each temporary memory which is in use at that time for receiving or for delivering data is connected to equipment on one only of its sides, i.e. equipment on its line circuit side only or to equipment on its facsimile signal input and output means side only. 30

2. / An installation according to claim 1, wherein the said £ temporary memories are connected to the said n line circuits via a coder-decoder (codec) circuit operating on a time shared basis and wherein each line circuit includes an auxiliary memory between its modem and the codec.

3. / A facsimile installation substantially as herein described with reference to the accompanying drawings.