DE3039949A1 - Telephone subscriber's appts. receiving teletext - has interface to exchange equipment to permit simultaneous use of line for digital signals and speech - Google Patents

Abstract

The subscribers appts. (FeAp) and exchange (VSt) equipment are buffered by frequency switches or filters (F1,F2) against the digital signals emitted by the information service equipment (BTZAL). Both services are connected to the subscriber by a single line (TnAL). The local modem (BTM) driving the television receiver (FSE-BT) and the modem (ASM) at the transmitting station are buffered and galvanically isolated from the telephone system. Information signals are transmitted in time or frequency ltiplex form. After selecting the information service required and its subsequent connection, which only takes a very short time, the subscriber line is free to accept calls whilst the data transmissions continue.

Description

Messaging facility

for special service traffic The invention relates to a transmission device for special services according to the preamble of claim 1.

When using special services such as 7eitansaLrt, lottery or Lotto / Toto numbers or FernsprechauStras2; S service by a participant Telephone line and exchange equipment not very long proven. It is different with special services such as sports club, stock status, theater or cinema service and similar services, especially when the new one is introduced Video text service, in which, depending on the subscriber's hunger for information, his Connection line and the input and selection levels of the exchange more or will be occupied for a shorter time. During the period of use of a special service the subscriber cannot be reached, even for important calls.

The object of the present invention was therefore to provide a device of the above type to indicate that it is inexpensive A @ t allows the IeilneElmer can also be reached if he's on a special service, for example Screen text service. With the help of this facility, it should it may be possible that the exchange to which the subscriber is connected via the connection line, not or only very briefly.

The solution takes place with the means specified in the claims.

In the essay "Some Design Considerations for Home Inter - @@ tive Terminals "by Williams L. Hughes and Samuel, O. Campbell in IEEE TRANSACTIONS ON BROADCASTING, Vol. BC-17, No. 2, dated June 1971 on pages 37 to 41 is an interactive one Universal home terminal with screen memory described, with which pictures are reproduced can be called up by the terminal user using the keyboard, from a remote computer center selected and transmitted for output on the screen will. On page 41, left column, last paragraph, the suggestion is made for the keypad to use a telephone line, with the keypad signals over the voice band should be raised so that simultaneous use of the Telephone line for calls and home terminalsre @ ourdaten möp; I am with the named one System, however, no further details are given for the implementation of this proposal and on the other hand it is only about the signal transmission from the Keyboard to the computer center, since the transmission of the selected video images in Video waveform is done over a TV (CATV) cable.

The invention has the advantages that the subscriber line not even during special duty operations is blocked that so that the switching center facilities are relieved and that the subscriber station facility Requires less effort for special services, since the voting procedure is not required. With the elimination of the relatively slow dialing procedure, the waiting time until production is increased a special service connection so small that the subscriber can no longer perceive it can, which makes the use of special services even more attractive will.

There now follows the description of the invention with reference to the figure Figure 3 shows an embodiment for the special services screen text.

With the on-screen text (BT) service, after pressing the appropriate key on the remote control device FB by the subscriber automatically establishes a connection via the subscriber line TnAL to the screen text center BTZ established, after which an image is shown on the television receiver screen over the same distance with screen text addition FSE-3T with a corresponding call for further keyboard input Then the remote control unit FB takes place.

The figure shows the crossover network F1 on the subscriber side and the Crossover F2 at the office end of the subscriber line TnAL, over the subscriber-side telephone set FeAp and the exchange by means of low-pass filters VSt can connect with each other and via the high passes the participant Teletext modem BTM and the official modem ArM Verlhirldtlns; ; ritf'-take can. The video text modem BTM is via a two-way line ZL with the subscriber Television receiver connected to the FSE-BT text supplement. On the official side is according to the invention the screen text central BTZ via a connection line BTZAL, connected via a PCM device PCME with several of the office-side modems ASM. I) .ldtlrf, the subscriber lines TnAL and the Connecting cable for the screen text central BTZAL exploited several times. Teletext modem BTM and Office counter modem ASMs work advantageously in a transmission range above of 16 KHz (charge impulses), with the screen text signals in the modem ASM using a clock supplied by the PCM device PCME are processed in such a way that them from the latter time slot correct; can be accommodated in the PCM frame.

Another advantage of the invention is that the transmission speed can be increased at least from the screen text center to the participant.

A further advantage is that the subscriber's video text modem BTM can be done via the television receiver, since the filter switch F1 is a galvanic Separation is achieved.

The exchange VSt is also relieved from the fact that the billing of the screen text fees is fully taken over by the screen text center will.

Claims (7)

Claims 1. Message transmission device for special service traffic between subscriber stations and a special service facility via connecting lines are connected to a switching exchange, characterized in that the Traffic in the outward and return direction on the connecting lines (TnAL, BTZAL) respectively takes place in multiplex operation. 2. Device according to claim 1, characterized in that the traffic in time division multiplex, in particular with delta modulation. 3. Device according to claim 1, characterized in that the traffic takes place in frequency division multiplex. 4. Device according to claim 1, characterized in that the traffic on the subscriber connection line (TnAL) in frequency division multiplex and on the connection line (s) (BTZAL) of the special service facility takes place in time division multiplex. 5. Device according to claim 4, characterized in that on both Ends of the subscriber line (TnAL) crossovers (F1, F2) and modems (M1, M2) for coupling / decoupling and modulation or demodulation of the special service signals are provided. 6. Device according to claim 4 or 5, characterized in that for transmission on the connection line (BTZAL) of the special service facility a PCM 30 system (PCME) is provided. 7. Device according to one of the preceding claims, characterized through the application at Videotext Service.