Service-integrated transmission and switching network for picture, sound and data.

0001The invention relates to a broadband integrated fiber optic network for supplying subscribers according to the preamble of claim 1.

0002Such a service-integrated message transmission and switching system is known from DE-OS 29 22 418, in which a video and an audio switching matrix in the center for supplying the subscriber with two TV and 10 VHF programs by the subscriber can be selected by means of a control signal in the reverse direction from the large number of television and radio programs offered.

0003Such a video or audio switching matrix requires cumbersome and complex cable routing in the head office, the greater the more programs the individual subscriber is offered at the same time. Current planning is based on three television programs from 16 offered and on a distribution of the signals to different subscriber numbers up to the size of a telecommunications network area. It can be seen that between the switching matrix and subscriber multiplexer for decoupling or interference suppression of the connection and control lines, a high cost, z. B. in coaxial technology, is required.

0004It was therefore the object of the present invention to specify a network of the above type, in which less line management effort is required on the switching side.

0005This object is achieved with the means specified in the claims.

0006By dividing a central switching network according to the invention into decentralized switching devices assigned to each subscriber and by supplying the broadband signals to be distributed via bus lines, very many lines are saved, for example only a number of 16 feed lines for TV are now required compared to the solution of the stand the technology with three times the number of participants to be connected. In the same way, the effort for the control is reduced.

0007In a further development of the invention, all subscriber-specific devices are combined, it being possible for optoelectronic converters, the BB and SB multiplexers, the switching functions and the associated controls to be accommodated in uniform slide-in cassettes. This summary makes it possible to manufacture the subscriber interface unit using high-integration technology, for example using rows of gates on customer-specific circuit chips.

0008In a further embodiment of the invention, by cascading selector switches, it is possible to expand the number of television programs or other broadband services as desired.

0009In a further embodiment of the invention, each subscriber interface unit contains a monitoring circuit, with which it is possible to switch off the parts of the subscriber interface unit that are not required, and thus to save electricity, on the basis of an identifier given by the subscriber station device, which characterizes the passivity of the subscriber.

0010In another embodiment of the invention, the bus lines for the broadband signals to be distributed are not designed as coaxial cables, but as microstrip lines in the course of the tub wiring, for example as a multilayer. Instead of coax plugs, cheap multiple plugs can of course be used.

0011For the rest, the construction according to the invention has the advantage of simple serviceability, good location of errors, minimal range of error effects and easy expansion of the number of participants.

0012There now follows the description of the invention on the basis of the figures illustrating the exemplary embodiments.

00131 shows, in one embodiment of the invention, a slot-in cassette shown in perspective, which contains, as a subscriber set, all subscriber-specific devices with broadband and narrowband multiplexers, with switching functions and associated controls, and the electro-optical converters. The horizontal bus lines carry the broadband signals such as TV channels, video telephone lines, radio, clocks and power supply. The fiber optic connection LWL, which leads to the subscriber, can be seen on the left front transverse side. On the rear transverse side are the narrowband signals SB to be conveyed (telegraphy, telephony, etc.) and possibly a video telephone line Bif^* connectable, which is mediated centrally.

0014FIG. 2 contains the block diagram for the subscriber set according to FIG. 1 (dash-dotted line). The broadband bus inputs can be seen on the left with Bif, TV and radio, with three TV signals or two TV signals and Bif being selectable from the Bif and TV signals, which together with the radio signal to which the narrowband signals ( ISDN) are added in a broadband pre-multiplexer BB-VOR-MUX, combined in a broadband multiplexer BBMUX and transferred via a switch to an electro-optical converter which feeds the fiber optic cable to the subscriber. In the reverse direction, the signals arriving from the subscriber are converted into electrical signals by means of optoelectronic converters and fed via a switch to a demultiplexer D-MUX, which outputs the narrowband signals ISDN and, if applicable, video telephone signals Bif. The phase adjustment of the signals required before the multiplexing is carried out by multiple sampling (punctured diamond).

0015The complex identified by the dashed outline corresponds to the subscriber interface unit TAE, the functions of which are summarized according to the invention on a highly integrated chip. Of course, the functions can also be implemented with standard integrated circuits and, if necessary, broadband coupling points.

0016It can also be seen how the characteristics of the subscriber station device are recognized from a narrow-band return channel (HKZ) and corresponding commands are supplied to a control and monitoring circuit, with the aid of which the parts of the subscriber set that are not required by the subscriber are switched off or the corresponding selection address character for a subscriber selecting a television program determined and fed to the corresponding selectors or decoders.

00173 shows a selector according to the invention by means of a block diagram. The channel selector according to the invention contains three similar devices, each consisting of a (<maths id="math0001" num=""><img file="EP0076362A2_D0001.tif" /></maths>) Decoder (<maths id="math0002" num=""><img file="EP0076362A2_D0002.tif" /></maths>) Demultiplexers and switches US exist. On the three demultiplexers (<maths id="math0003" num=""><img file="EP0076362A2_D0003.tif" /></maths>) the 16 broadband channels E1 to E16 are managed with binary, digital signals (e.g. ECL interface, approx. 70 megabits / sec each). With the help of 3 by 4 address inputs and corresponding decoders, a broadband channel is switched to one of the outputs D1 to D3. With the help of the switches US1 to US3, either the signals D1 to D3 or the signals B1 to B3 are switched through to the outputs A1 to A3 of the channel selector. 3 bits are provided for switch selection. The changes in the addresses take place very slowly, for example in the range of seconds, so that the address lines can be routed between the broadband channel lines as shielded or coupling lines. The channel selector is supplied with current via the connections VCC, and the channel selector can be switched off from the power supply via the connection PD.

0018Fig. 4 shows a broadband bus, the TV program rails at the beginning and at the end are almost completed with their wave resistance. The taps to the subscriber sets are high-resistance, the resistors sit on the tub wiring board, so that reflections caused by the plug connections have no effect. The amplifiers drawn at the bus input are, for example, ECL drivers, which are required once for each tank.

00195 shows a circuit suitable for decentralized structures for decentralized telephony switching for 12 subscribers and 6 paths, external connections which can be connected to the Bif paths by means of line sets or conference circuit sets not being shown.