DE3002188A1 - REMOTE COPY-DIGITAL TRANSMISSION SYSTEM - Google Patents

Description

SIEMENS AKTIENGESELLSCHAFT Our mark

Berlin and Munich VPA 80 P 7 8 0 1 OE

Facsimile digital transmission system

The invention relates to a transmission system for the transmission of fax digital signals in a sub-channel of a 64 kbit / s standard channel in which in Telephone digital signals are transmitted to a further sub-channel. One such, transmission, in telephony and remote copying, for example, into two 32 kbit / s subchannels carrying corresponding ΔΜ signals a 64-kbit / s standard channel can proceed (DE-AS 27 29 689), is the transmission and in one Switching (transmission) of digital signals in corresponding 64 kbit / s standard channels future integrated services telecommunications network (ISDN) to be expected, to which then '. subscriber side also corresponding Digital telephones and digital facsimile machines will belong.

However, until such an integrated services digital network is introduced and further completed already a large number of today's common audio-frequency analogue signals emitting fax machines on the Be in operation in the market and with the user within the framework of the conventional analog telecommunications network; these analog facsimile machines To be able to continue to use it in a digital network as well, the invention shows one way.

According to the invention, a transmission system of the type outlined above is characterized in that a known Way audio-frequency analog signals emitting and receiving analog fax machine via a digital modulator / demodulator with which to summarize the telephone digital signals and facsimile digital signals or expanding sub-channel multiplexer / demultiplexer Spr 1 KeI /18.1.80

130030/0678

connected is.

The invention makes it possible in ain @ m future service = integrated digital network in addition to the corresponding digital telecopiers also existing analogue = -F © rnköpler * devices of the already introduced fax service reiter- » to be able to usej it thus enables an ent · » . Significant cost savings for the full service life such analog fax machines and thus facilitates at the same time the use of the digital network.

In further. Embodiment of the invention can with d © m Analog fax machine a J ^, modulator / demodulator be connected; such a 4-modulator / ~ Damodulator On the one hand, it is relatively inexpensive and, on the other hand, enables relatively fast remote copying o

In a further refinement, a ^, - modulator ¹ · / demodulator can also be provided in the digital Faraspreeh device; the lower bit rate requirement for telephony compared to PC modulation with at least not reduced voice quality enables a correspondingly higher bit rate for remote copying and thus correspondingly lower demands on the digital modulator downstream of the analog remote copier and / or a corresponding acceleration of the remote copying process.

The invention is explained in more detail with the aid of the drawing.

The drawing shows schematically, to the extent necessary to understand the invention, a remote copy = digital signal transmission system according to the invention with a subscriber station TIn of a digital telecommunications network, via a connection line Al may subscribers ¹

130030/0678

place Tin next to one that is no longer shown in the drawing Digital switching parts of the digital telecommunications network be connected.

As can be seen from the drawing, the subscriber station TIn can initially be a digital telephone device Fe with keypad, display, filter, analog / digital converter, sending and receiving with separation of the direction of transmission as well as the clock generation and synchronization enabling transmission device and the Have signaling character exchange with the exchange processing control device ST, the latter can be implemented in particular by a microprocessor. The subscriber station TIn also has a fax machine Fax on; it may be a conventional analog telecommunications network (for example in the context of today's fax service) to be operated analog fax machine.

In a corresponding manner, further subscriber stations of the subscriber station shown in the drawing can also be used TIn containing digital telecommunications network trained without this being shown in the drawing. For the transmission of messages to and from them Subscriber stations of the digital telecommunications network like on the connecting lines, as shown in the drawing Connection line Al, and not on in the drawing further illustrated transmission routes as well as in switching centers of the digital telecommunications network Standard telecommunications channels with a bit rate of 64 kbit / s each (per transmission direction) are available, with the 64 kbit / s standard channel having two telecommunication sub-channels of for example 32 kbit / s each, one for telephoning and the other for faxing is provided.

130030/06 78

So now for remote copying in the digital telecommunications record also the analog telecopier indicated in the drawing, emitting audio-frequency analog signals at its output a Fax used \ tferden is him A digital modulator is connected downstream on the transmitting side and a digital demodulator is connected upstream on the receiving side «, The digital modulator and demodulator are expediently provided by an Ä modulator-modulator (Α modem) A / A given, in which the transmitting side (in the Δ, modulator)

"Io depending on the sign of the difference between a sampled value of the analogue fax signal and a prediction value (ΔΜ bit), which is formed in principle by adding up all previous difference values and changes in steps from sampling point to sampling point," O ⁵⁵ or ^W 1 ^{n is} generated and an integrator of a so-called Α decoder is discharged or charged in a feedback path of the Α modulator and on the receiving side (in the A demodulator) in accordance with the ΔΜ bits.

The Α modem A / A is connected to a said digital telephone Fe associated sub-channel multiplexer / demultiplexer Muldex connected, the Fernspreeh-Dlgitalsignale and the remote copy digital signals to a common _t in the outgoing 64 kbit / s unit channel flowing bitstream bundles, in the context of telephone signal bits and facsimile signal bits each occur at predetermined stalls, or in the reverse direction of transmission the telephone signal bits and facsimile signal bits contained in the incoming bit stream fan out again on telephone Fs and facsimile fax. The sub-channel ^ multiplexerZ demultiplexer Muldex, which, as indicated in the drawing, can be controlled by the control device ST, can be operated cyclically

130030/0678

- 1 - VPA 80 P 7 8 0 1 DE

Be formed switch; it is also possible to use the sub-channel multiplexer / demultiplexer function with the help of a microprocessor (e.g. type SBC 80/20) and a freely addressable read-only memory (ROM = read only memory), as is basically known (from FIG. 2 of DE-AS 28 27 040) and therefore need not be further presented here. Of the The microprocessor can be formed by a microprocessor already contained in the control device ST be.

With the circuitry addition explained above with reference to the drawing, the analog remote copier Fax a digital telephone Fe and analog fax machine Fax having subscriber station TIn simultaneously with the digital telephone Fe operated in one subchannel of the 64 kbit / s standard channel in a second Partial channel are operated so that between two such subscriber stations of the digital telecommunications network simultaneously Telephoning and faxing is enabled. A 32 kbit / s sub-channel, for example, can be used for fast remote copying be provided in the digital signals of the one formed by a Α modulator as a fax Digital modulator (Α / Λ) generated ΔΜ bits are transmitted; expediently then also has the digital telephone set Fe for analog / digital conversion a ^ modulator (and demodulator) A / D, so that then in the other telephony sub-channel which also enables a bit rate of, for example, 32 kbit / s or only 24 kbit / s of the 64 kbit / s standard channel digital telephony signals also transmitted in the form of AM bits will.

130030/0678

BATH ORIGINAL

Claims (3)

VPA SO P 7 8 0 1 OE Claims 1 / Transmission system for the transmission of facsimile digital signals in a subchannel of a 64 kbit / s standard channel in which digital telephone signals are transmitted in a further subchannel, characterized in that a facsimile machine which emits and receives audio-frequency analog signals in a known manner A digital modulator / demodulator (A / A) is connected to the sub-channel multiplexer / demultiplexer (Muldex) that summarizes or fanning out the telephone digital signals and Fernkopier ™ digital signals. 2. Transmission system according to claim 1, characterized by an A modulator / demodulator (A / A) connected to the analog fax machine » 3. Transmission system according to claim 2, characterized in that the digital telephone set (Fe) also contains a & modulator / demodulator (A / D). 130 0 3 0/0678
r ORIGINAL BATHROOM