FR2474261A1 - DIGITAL TRANSMISSION SYSTEM FOR FAX - Google Patents

Abstract

THE INVENTION RELATES TO A DIGITAL TRANSMISSION SYSTEM FOR A FAX. IN THIS TRANSMISSION SYSTEM INCLUDING A TLN SUBSCRIBER STATION CONNECTED TO A CENTRAL THROUGH AN AL LINE, A FAX TELECOPY APPARATUS DELIVERING AND RECEIVING ANALOGUE SIGNALS AT VOICE FREQUENCY IS CONNECTED BY A DIGITAL MODULATOR OF THE DIGITAL MODULATOR FROM A DIGITAL MODULATOR TO THE MULTIPLEXER A MULDEX PARTIAL CHANNELS COMBINING OR DISTRIBUTING THE DIGITAL TELEPHONY SIGNALS AND THE DIGITAL FAX SIGNALS. APPLICATION IN PARTICULAR TO TELECOMMUNICATION SYSTEMS.

Description

The invention relates to a trsminsme of trnsminssion c.e..in to transcribe

  This data is copied to a partial channel of a 4 kbits uni channel in which telephony digital signals are transmitted in another partial channel. A transmission, in which the telephony and the facsimile can for example take place in two partial channels at 32 kbit / s, carrying corresponding signals, of a 64 kbit / s unit channel. the public inspection in Mo. 27 29 689), may in the future make his incursion

  in a future telecommunications network (ISDI.)

  service and allowing the transmission and communication

  nication (retransmission) of digital signals in corresponding 64 kbit / s unit channels, digital telephones and digital facsimile machines

  corresponding then to be provided on the subscriber side.

  Until the introduction and full implementation of such a digital network integrated into the service,

  many of today's conventional fax machines,

  both voice-frequency analog signals will have already been put into service on the market and at the user, within the framework of the usual analog telecommunication network; the present invention shows a way to use

  analog fax machines also in a digital network.

America.

  According to the invention, a transmission system

  A mission of the type indicated above is characterized in that a fax machine, delivering and receiving, in a known manner, analog signals with a voice frequency, is

  connected via a modulator / demodulator

  to the multiplexer / demultiplexer of partial channels

  combining or distributing the digital television signals

  voice and signals: digital fax.

  The invention makes it possible to continue to use

  in a future digital integrated network in the service, besides corresponding digital fax machines, also nalnaogicues telecomers cj; It is therefore possible to use the same name as "teles" in a product, which means that it also provides a corresponding savings in terms of the total service life of such analog fax machines and thus facilitates simutaneous use. born of the

resume numérioue.

  According to another: the embodiment of the invention

  a modulator / demodulator can be connected to the tele-

  enalogicue copier; such a modulator / demodulator A is of a relatively inexpensive nt and other ready

  a relatively fast fax.

  According to another embodiment, one can

  provide equal modulator / demodulator A in the

  such a telephonic n-nerique; the need for a dual

  Since telephony, which is less than X, a coded impulse modulation for at least equal loudness of the conversation, allows a corresponding higher bit rate for the facsimile and imposes lesser demands on the modulator. digital line6 in series and downstream of the fax machine and / or

  achieves a corresponding acceleration.

facsimile.

  By way of example, it has been described below and illustrated schematically in the following drawings:

  r_ lsation of the object of the invention.

  These drawings show schematically, with a scope necessary for the understanding of the invention,

  a system for transmitting digital tele-

  in accordance with the invention comprising at a post of

  born from a telecommunications network. It will be assumed that, via a connection line A1, the subscriber station Tln is connected to a digital cable, not shown in the drawing, of the digital telecommunications network. As can be seen in FIG.

  subscriber Tln may comprise first of all a tele-

  digital phonic Fe to keypad selection

  TT, a display device Dy, a filter F, a conver-

  digital / analogue A / D weaver, a transmission device

  UE mission for transmission and reception with transmission direction separation and cadence and synchronization, and in particular an ST controller also performing the exchange of symbols or signaling characters with the central office, said control device which can be produced in particular according to the microprocessor technique. The subscriber station

  In addition, there is a fax fax machine.

  an analogue fax machine for use in an analogue telecommunications network

  usual (for example in the context of the current service

  under the name of "telefaxw"), for example a fax machine

  marketed under the name "Hell HF 1048".

  Other subscriber stations of the telecommunication network

  Numeric communications to which belongs the subscriber station Uln shown in the drawing, may be constituted correspondingly without this being shown in the drawing. For the transmission of information from and to these subscriber stations of the telecommunication network

  number, it will be assumed that there are telecommunication unit channels

  munication with 64 kbit / s bit rate

  (for each direction of transmission) in trans-

  mission not represented in the drawing as well as in central offices of the digital telecommunications network, the

  64 kbit / s channel channel which may have two separate channels

  each of 32 kbits / s, one of which is intended for telephony and the other of which is

intended for faxing.

  In order to be able to use also for

  copy, in the digital telecommunication network,

  the fax machine fax shown on the drawing and

  delivering at its output analog signals with frequency

  speech, a transmitting modulator is connected on the

  series and downstream of this facsimile machine and, on the

  ception, a digital demodulator in series and upstream

  fax machine. The digital modulator-and the demodulation

  digital converter are suitably constituted by modulator / demodulator a (Modem A) A / L, in which, on the transmitting side (in modulator A), an element of

  binary signal (bit A M) "0" or "1" is produced as a function

  the sign of the difference between a value of

  the analog signal from the fax machine and a value

  provided in principle by summing all the

  their previous differences and varying in steps from one moment to another moment of exploration, while in a coupling path by reaction of the modulator as well as on the reception side (in the demodulator 4), a

  integrator of what is called a decoder is

  ge or is loaded according to the bits L M. Such Mo-

  are known in principle - for example under the

  form of what is called the Codecs of Motorola MC 3417 -

  and do not need to be explained in more detail here.

  The Modem tà, A / t, is connected through the intermediary

  from a junction line ob to a multiplexer / demulti

  "Partial channels" plexor "Muldex" associated with the phone

  Fe which brings together the digital signals of

  telephony and digital facsimile

  a common bit stream flowing in the originating 64 kbit / s channel and in whose frames telephony signal bits and

  bits of fax signals at predetermined locations

  terminated, or which distributes, in the reverse direction of transmission, the telephony signal bits and the facsimile signal bits contained in the bits

  arrival, again between the Fe phone and the

  fax. The multiplexer / demultiplexer 'Muldex' with its

  partial numbers which, as shown on the

  sin, can be controlled from the controller ST, can be achieved by means of cyclically operated switches; this is illustrated in Figure 2. It is also possible to perform the function of the multiplexer /

  demultiplexer of partial channels using a micropro-

  caterer (for example of the type referred to as INTEL SAB 8080) and a freely addressable read-only memory (ROM) in a microcomputer (for example of the INTEL SBC / 20 type), as is known from the point of view of the principle (d after Figure 2 of German Patent Application Laid-Open No. 28 27 040), and

  so no need to be here represented in more detail

  EEA. The microprocessor can be constituted by a micro-

  processor contained in the controller ST.

  As can be seen in Figure 2 (whose

  representation is like Figure I a modern representation of

  nofil), the multiplexer / demultiplexer'Muldex '' of partial channels may comprise (for each direction of transmission) a switch U whose bit rate is controlled via a transmission conductor bt.

  bit rate by a rate device T of the device

  tif of the UE transmission and which connects the junction line is, extending between the multiplexer / demultiplexer of

  "Muldex" partial channels and the transmission / reception

  S / E of the EU transmission device, alternatively

  at the junction line ib, extending between the multiple-

  "Muldex" partial channel demultiplexer and conver-

  the analog / digital A / D weaver (in FIG. 1), and the junction line b1 extending between the partial channel multiplexer / demultiplexer Muldex and the modulator / demodulator AA / to (in FIG. FIG. 2 shows that a switch S, controllable via a control line sy from the controller ST via the control line, is from a SyE receiver of synchronization words of the UE transmission device via a command line

2474261-

  sy, is inserted in the transmission line bt of the binary rate. If the switch S receives a mixed communication signal produced by the control device ST, for example by actuating a mixed communication key MK of the selection keypad TT

  (in FIG. 1) and by means of which, for example, a

  SyS director of synchronization words can be triggered

  for example also through the li-

  control junction node os (in FIG. 1) in the transmission device UE (in FIG. 1), or receives a control signal via the command line st or receives such a control signal

  concerning a synchronization word received by the receiver

  synchronization word SyE, via the command line sy, the switch S is closed synchronously from the point of view of the partial channels, so that the switch U, interconnecting in the case of the example at rest the telephony channel, then performs a back and forth switching at the binary rate

  in synchronism from the point of view of the partial channels.

  With the complementary system relating to the

  circuit technique, previously explained in

  With regard to drawings, the tele-

  fax-to-analog fax machine of a Tln subscriber station,

  both a digital telephone device Fe and a television

  analog fax copier, together with the digital telephone device Fe, operating in a channel

  64 kbit / s channel channel in a second channel.

  In this way, telephony and facsimile are possible simultaneously between two subscriber sets of this type of the digital telecommunication network. For a fast fax, for example, a partial channel at 32 kbit / s may be provided, in which bits t M produced by the digital modulator (A t) formed by a modulator t, are transmitted as digital facsimile signals; appropriately the device

2474261.

  Digital Phone Fe also contains, for the

  analog / digital conversion, a modulator (and a

  modulator) AA / D, so that the telephony digital signals are also transmitted in the form of LM bits in the other telephony partial channel of the 64 kbit / s channel channel, allowing a bit rate of, for example also 32 kbits / s or even just

24 kbps.

2474261.

Claims (3)

  1) A transmission system for transmitting digital facsimile signals in a partial channel of a 64 kbit / s unit channel, in which digital telephony signals are transmitted in another partial channel, characterized in that a facsimile machine (Fax), delivering and receiving, in a known manner, signals   voice-frequency analogue, is connected through   a digital modulator / demodulator (A / A) to the multiplexer / demultiplexer of partial channels (Muldex) combining or distributing the digital   telephony and digital facsimile signals.   2) Transmission system according to claim 1, characterized by a modulator / demodulator A (A /)   connected to the analog fax machine (Fax).   3) Transmission system according to claim 2, characterized in that the telephone device   numerical (Fe) also contains a modulator / demodulator A (A / D).