FI90173B - FOERFARANDE OCH ANORDNING FOER ANSLUTNING AV EN DATAMASKIN TILL ETT DIGITALT TELEFONNAET ELLER ANNAT DIGITALT OEVERFOERINGSSYSTEM - Google Patents

Description

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The present invention relates to a method and a system for connecting a computer to a digital telephone network or other digital transmission system by means of an interface unit which is connected to a computer interface.

Currently, computers are connected to an analog telephone network 10 by a voltage interface, i.e., a modem, which is connected to an analog subscriber interface of the analog telephone network. Modems establish voice-based connections to another subscriber device on the network.

In an analog telephone network, computers can in practice only transmit character-based information, i.e. data, which is thus forced to be transmitted on a voice basis. The transfer rates achieved in this way are low. New digital transmission systems require a substantially different architecture to take full advantage of digital connections. An example of a digital transmission system is the integration of different electronic subscriber services, such as telephone, cable television, etc., into the same subscriber connection. The international ISDN standard (Integrated Services 25 Digital Network) has been developed for digital signal transmission. In the ISDN basic interface, the so-called The S-interface bus connects the network terminal to one or more terminals. The S-interface of the terminal interface is defined in CCITT Recommendations 1.411, 1.412 and 1.430 and uses a channel structure 2B + D with a B-channel rate of 64 kbit / s 30 and a D-channel rate of 16 kbit / s.

The ISDN digital connection can thus be used to transmit data directly in digital form, typically at a speed of at least 64 kbit / s, as well as audio encoded in digital form, by means of a computer such as a personal computer. Connections can be made to both digital 2 90173 and analog terminals. Thus, a computer can receive, transmit, and process digital audio, such as speech, at a rate provided by an ISDN interface under the control of either its own processor or the control processor on the interface card.

It is an object of the present invention to provide a method and system for connecting a computer or similar workstation to a digital telephone network, such as an ISDN network or a similar digital transmission system having an ISDN connection. The method according to the invention is characterized in that the communication is arranged according to the time division principle in the digital serial bus (15) of the interface unit (9) by means of a switching field (14), whereby digital voice data and / or signaling channels (B1, B2, D) so that digital audio, data, and / or signaling information can be read / written by a computer (1) to the serial bus (15) via the computer interface bus (6), 20 and that the interface unit ( 9) can send or receive data independently at desired time intervals.

Other preferred embodiments of the invention and the system according to the invention are characterized by what is stated in the claims below. The invention will now be described in more detail by way of example with reference to the accompanying drawings, in which

Figure 1 shows a known solution for connecting a computer to a public telephone network.

Fig. 2 shows a computer connected to a digital interface 30 according to the invention, corresponding to Fig. 1,

Figure 3 shows a block diagram of a digital interface based on time division technology according to the invention,

Figure 4 shows one way of transmitting data or digital audio in the interface according to the invention, 35

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Figure 5 shows a solution for implementing a digital telephone according to an embodiment of the invention,

Figure 6 shows a solution according to an embodiment of the invention for connecting a computer's own interface circuit to a digital interface,

Figure 7 shows a solution according to an embodiment of the invention for extending the architecture of a digital interface,

Figure 8 shows an example of the division of labor between the tie-10 token and the interface unit according to the invention.

Currently, computers are connected to an analog telephone network in an arrangement similar to Figure 1. The personal computer 1 is connected by a voltage connection E to a modem 2 connected to the analogue subscriber interface F of the analog telephone network 3. The modem 2 establishes a voice-based connection to another subscriber device 4 in the network 3. The voltage connection E is usually implemented by a circuit that changes the TTL level signal V .28- level (+ - 12V).

In the computer's own architecture, this interface 20 can be implemented as shown in Figure 1. The computer (PC) has a processor 5 which controls the bus 6. The bus 6 is connected to memory circuits 7 which contain the program code required by the processor 5 and the data processed by it. The bus 6 is also connected to an interface circuit 8, the registers of which are processed by the processor 5 25; the interface circuit 8 transmits and receives data from the registers / registers to / from the voltage interface E. The interface circuit 8 may also be connected to a separate interface bus (e.g. ISA or EISA bus) formed for the interface circuits, which is separated from the processor internal processor. interface circuit. The bus is located in the address space of the processor, but it can have its own clock frequency, for example.

Figure 2 shows a computer 1 connected to a digital ISDN connection according to Figure 1. In the ISDN network 35, data can be transmitted directly in digital form via interface G at a transmission rate of typically 64 kbit / s provided by it. Sound, such as speech, which can be digitally encoded can be received, transmitted and processed in connection with both digital and analog terminals 4.

The connection to the digital transmission system is implemented with an interface unit installed in the computer 1. This can be a circuit board to be installed in the expansion interface of the computer bus, which in this example is called the interface card-10. In the architecture of the interface unit according to the invention, it is essential that the bit stream transmitted by the digital interface G is directed to the internal serial bus 15 of the interface card, the buses of which can be freely connected to each other by means of the switching field 14. Furthermore, these 15 buses can be connected by suitable interface circuits 16 to an internal bus 17 controlled by the processor 12 in the interface card. The elements referred to by reference numerals 14-16 in Fig. 3 are shown in reduced symbols in the absence of established symbols. The operation and purpose of organs 14-16 will be described in more detail in the future. The computer processor 5 and the bus 6 themselves have the following types of connections to the interface card: an interface circuit system 10 corresponding to the interface circuit 8 of Figure 1, and a dual port memory 11; from these data and sound are obtained e.g. access to the processor 12 via the bus 17. In the method according to the invention for connecting a computer and a digital transmission network, it is essential that the interface card 9 provides a basis for a wide variety of digital transmission applications, the features of which can be programmed to be executed by both processor 5 and processor 12. Flexibility based on different serial and parallel buses and the connection between them is key.

The interface shown in Figures 2 and 3, which is an ISDN interface by way of example, typically comprises a set of 35 digital channels implemented with time division technology,

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5,90173 as channels D, B1 and B2 in Figure 3. In the basic ISDN S-interface, the speeds of these channels are 16, 64, and 64 kbit / s. The D-channel is used for call control and the B-channels for the transparent transmission of data or voice through the ISDN network 13.

According to Fig. 3, the serial bus 15 of Fig. 2 can be constructed from a plurality of conductors J1 ... Jn, each of which has a set of time slots A implemented with time division technology. Time division technology (e.g. TDM) is a known technique and will not be described in more detail here. The time division technology of the different serial buses 10 is supported by one or more commercial integrated circuit manufacturers, and thus data or digital audio from different sources / sources can be connected to the time slots 15 of the serial bus 15 using commercially available integrated circuits, hereinafter referred to as serial bus circuits.

Fig. 3 shows a serial bus circuit 18 which connects the digital channels D, B1 and B2 of the digital telephone interface G in the reception and transmission directions to the time slots of the serial bus 15. The solution 20 according to the basic idea of the invention, which enables freely configurable time slots by means of the switching field 14, is also well suited for interfaces other than 2B + D interfaces, e.g. a 30B + D structure. In addition, there are applications in which one channel can reserve more time slots, which in this exemplary case is illustrated by channel B2, which has reserved two consecutive time slots for itself. Thus, any other serial bus circuit 16 associated with the serial bus 15 can access the data from the interface G by reading the correct time slot J1 ... Jn from the correct time slot, and on the other hand one such other serial bus circuit 30 can control the data from the interface G to a specific channel by writing the correct data. conductor Jl ... Jn to the correct time interval.

Figure 3 shows one such other serial bus circuit 16, which implements a certain way of connecting the parallel bus 17 and the serial bus 15 to each other (vr 1 ..

6 c Π 7 o Fig. 2). The serial bus circuit 16 contains registers R that can be read and written from the interface bus 17. Some of these registers R are control registers that control the operation of the serial bus circuit 16, while some are data registers 5 whose contents are either written to a time slot or retrieved from something (perhaps determined by the control register). ) from time slot A. This causes the data to be transferred exactly as desired between the interface bus 17 and the serial bus 15, and further between the channels B, 10B1, and B2 of the interface bus 17 and the interface G.

The flexibility and versatility of this electronic circuit is complemented by a switching field 14 capable of switching any time slot of the serial bus 15 to any other time slot. These connections can be controlled from the interface bus 17 by writing to the control registers of the connection field 14 (not drawn). Thus, each of the serial bus circuits 18 and 16 may operate, for example, in certain fixed time slots, and the switching field 14 determines how data travels between these time slots and thus the serial bus circuits 20. The time slot-based switching field is known in the art, and there are several manufacturers of switching field integrated circuits (e.g., Mitel and Siemens), so the operation of the switching field will not be described in more detail here for a person skilled in the art.

25 What has been said above and will be said below about the processing of data in the serial bus 15 also applies to digital voice, because the serial bus 15 does not take a position on what digital information is transmitted in the time slots. It should further be noted that the channels B1, B2 and D30 of the interface G are only examples of the range of channels that may be included in the subscription to the digital telephone network or a similar digital transmission system.

One very central factor in a connection such as Figure 3 is the timing, since the interface G operates in sync with the clock of the ISDN-ver-35 con 13, while the bus 17 operates in the clock of Figure 13.

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Γ '· Ί Ί * 7 7 ·: 1 7 Ο 2 CPU at 12 beats. Serial bus synchronization is the timing that prevails in the serial bus 15, in the switching field 14, and in the part of the serial bus circuit 18 between the serial bus and the interface that is connected to the serial bus 15. The serial-5 synchronization can be obtained from the interface G or a series of pathways of anxiety; in this way, the interface card can operate even without a connection to an ISDN network 13.

Figure 4 shows one way of transmitting data or digital audio 10 between the interface circuit system 10 and the serial bus circuits 16a and 16b, such as the dual-port memory 11 and the serial bus circuit 16, shown in Figures 2 and 3. The processor circuit 12 and the DMA circuit 19 controlled by it transfer information between the circuits 10 and 11 and the circuits 15a and 16b. For example, the interface circuit 10 may include registers R1 ... Rn addressable from both the computer bus 6 and the interface card bus 17. The dual port memory circuit 11 includes a number of memory locations M assignable from each bus. It is essential to transfer data and 20 digital audio from the computer bus 6 to the serial bus circuits 16a and 16b, then to the serial bus 15 and from there to the ISDN interface G (cf. Figures 2 and 3). , and correspondingly in the opposite direction.

The above technical explanation shows how 25 e.g. digital channels of an ISDN network can be obtained on an interface card, how they can be freely connected to time slots on the card's serial bus, and how data or digital audio can be read and written to them from a computer bus. In particular, it should be noted that the ISDN network interface 30 in the computer is independent of the applications used, and that both the computer and the interface card processors 5 and 12 can be programmed to serve this digital communication between the computer and ISDN.

Figure 5 shows how external devices can be connected to the interface card, in this example an analog 8 c-173 handset. Other external devices can be devised for a wide variety of applications. The analog telephone handset 20 is connected by an analog telephone connection A to an adapter circuit 21, which is e.g. a commercially available serial bus circuit within the meaning of the description above. Circuit 21 includes a digital-to-analog converter 22 that converts circuit 21 digital audio from a particular serial bus 15 to an analog format for the speaker of the handset 20. Correspondingly, the circuit 21 includes an analog-to-digital converter 23, 10 which converts the analog audio from the microphone of the handset 20 into a digital format for writing to a specific time slot of the serial bus 15. This operation (and other functions of the circuit 21) is controlled by control registers 24 which can be read and written by the interface card processor 12 via the interface card's internal interface bus 17. In this way, a digital telephone can be implemented with the help of an interface card.

If necessary, the computer processor 5 (Fig. 2) can control this event by transmitting commands directly to the processor 20 12, for example via the two-port memory 11 according to Fig. 2.

Figure 6 shows a case where the external device is the computer's own interface circuit, i.e. an integrated circuit connected to e.g. a PC computer bus. The connection of the conventional serial interface circuit 8 to the digital transmission system shown in Fig. 1 is realized according to Fig. 6 by a commercially available serial bus circuit 25 which adapts the TTL-level voltage connection Eb of the circuit 8 to the time slots of the serial bus 15. Here, a certain framing is utilized, which is formed by the internal connection SF of the circuit 25 when transmitting and the connection FS is released when received. In this way, the conventional data rate of the interface circuit 8 is adapted to the higher data rate of the serial bus and ISDN.

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With respect to the interface circuits, the procedure can be as in Fig. 7, where the interface circuit 8 is on the interface card 9, or so that the interface card has a TTL-level connector for the Eb interface, or even a modem-mating connector for a V.28-level (+ -12 V) serial connection. (cf. connection F in Figure 1). In this way, the computer's own hardware or software can use the connection of Figure 6 in exactly the same way and with the same software as the connection of Figure 1.

In summary, therefore, with the current 10 commercially available serial bus circuits, a large number of external devices can be connected to the basic architecture of Figures 2-4; these "external devices" can also be internal to the computer, so that emulating protocols and external connections already known to the computer ensures full software compatibility.

As an embodiment of the invention, the computer architecture can be easily expanded as shown in Fig. 7 by designing different expansion cards 26. According to the example of Fig. 7, the connectors C1 and C2 (between which there may be, for example, a flat cable C3) for the expansion card 26, the TTL-level conventional serial interface Eb shown in Fig. 6, which continues to the expansion card as the serial interface Ex, one or more of the data line pairs Jx of the serial bus 15,

Thanks to this expansion, any connector or device 27 on the expansion card can transfer conventional serial interface data 30, taking advantage of the connection of Figure 6 (device 27 in Figure 7 replaces 8 in Figure 6). In addition, any serial bus circuit 28 operating in serial bus slots may be located on the expansion card. The interface card processor 12 can control any of the circuits 29 on the good expansion card via the bus 17 extension 17b.

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It is particularly important to note that the serial bus circuit 28 can connect to the interface card an interface Gb of an ISDN network 13b which is not supported by the normal ISDN interface on the card according to Figures 2 and 3. This is important 5 because there are technically different interfaces to the same digital transmission service, thus requiring different serial bus circuits 28. This extensibility further makes the interface card compatible with many future digital networks and transmission systems.

Of course, the circuits 27, 28 and / or 29 in Figure 7 may be one and the same circuit. This is, of course, only an example of a flexible extension of the architecture of the basic interface card according to the invention with expansion cards; almost any interface card busses and interfaces can be expanded with expansion cards.

The connection and interaction between the computer and the ISDN network and other devices behind the ISDN connections is thus based on the program code 20 executed by both the computer's own processor 5 and the interface card processor 12, as well as the interaction between these program codes. In particular, the processor 12 of the interface card can almost completely take care of establishing connections via the ISDN network 13 to other devices 4 by means of the software located in the memories of the interface card (cf. Fig. 2).

This is a very important feature that distinguishes the present invention from known systems in which the hardware corresponding to the ISDN interface card is directly under the control of the computer's own processor.

Figure 8 illustrates this principle. The processor 5 of the computer 30 executes the application programs AI ... An, and the processor 12 of the interface card executes e.g. switching and signaling technical programs Bl ... Bn. The busses 6 and 17 and the electronics between them, such as the circuits 10 and 11, provide the communication connections between the processors 5 and 12, i.e. a flexible means of realizing exactly the desired li 11 <^ · 7ο communication between the program sets AI ... An and Bl .. .Bn. The switching and signaling technical programs Bl ... Bn can perform e.g. the following tasks, indicated by i ... iv in Fig. 8: 5 i: control of the switching field 14 for switching time slots in the serial bus 15, ii: transmission and reception of data via the serial bus circuits 16, iii: an important special case of ii is the independent execution of signaling-10 protocols ISDN 13 using another signaling channel D (Fig. 3) to establish calls, and iv: another important special case of ii is the execution of data transmission protocols using data transmission channels B1 and B2 15 (Fig. 3) with other subscriber devices 4, for example to transfer data from a computer to a device 4 .

The essential lesson of this example is that the computer application programs AI ... An perceive these functions 20 i ... iv as automatic and can control them, if necessary, via an electronic connection consisting of buses and interface electronics (6, 17, 10, 11).

In the same way that the programs ΒΙ.,. Βη of the interface card are able to flexibly serve the computer programs 25 Ai ... An, they are also able to serve the external devices shown in Figures 5 and 6 as well as the expansion cards shown in Figure 7.

It will be apparent to those skilled in the art that the various embodiments of the invention are not limited to the above examples, but may vary within the scope of the claims below.

Claims (14)

Method for connecting a computer (1) to a digital telephone network or other digital transmission system by means of an interface unit (9) which is connected to the computer's connection bus, characterized in that the traffic is arranged according to a time distribution principle in the digital serial bus system (15) of the interface unit (9) by means of a switching field (14), whereby digital audio, data and / or signaling channels of a digital telephone network or transmission system are connected to a serial bus system (15) (13) say that digital audio, data and / or signaling information can be read / written with the computer (1) on the serial bus system (15) through the computer's connecting bus (6), and that the interface unit (9) can transmit or receive data independently at desired time intervals. 2. A method according to claim 1, characterized in that the interface unit (9) can, by means of its own processor (12) and bus (17), automatically form a connection with the digital telephone network or transmission system (13) through the channels of the digital telephone network interface (G) using various contact formation and / or data transmission protocols, and provide a time interval connection for the serial bus system (15) for these contacts, and the computer controls the function of the contact through an interface circuit system located in the interface unit (9) (10) and / or double port memory (11). 3. A method according to claim 1 or 2, characterized in that, by means of the interface unit, such external devices (20) are connected to the digital telephone network or transmission system (13) which cannot as such be connected to the computer (1). ). Method according to claim 1, 2 or 3, characterized in that the computer is connected with said interface unit (9) to the digital telephone network f '1 Ί 7' 16 '' / J or the transmission system (13) by means of the interface unit emulate some of the external interfaces (E, F) used by said computer and / or its programs. Method according to any of claims 1-4, 5, characterized in that one or more expansion boards (26) are connected to said interface unit (9), with which the electronics and / or programs of the interface unit (9) are extended to a suitable network. or transmission system (13b) with which communication with the interface unit alone is impossible. 6. A system for connecting a computer to a digital telephone network or other digital transmission system by means of an interface unit connected to the computer's connection bus, characterized in that the interface unit (9) has a digital serial bus system (15) and a switching field (14), by means of which the traffic in serial bus systems is carried out according to a time distribution principle, and that digital audio, data and / or signaling channels of said network 20 or transmission system (13) are connected to the serial bus system (15), so that digital audio, data and / or signaling information in the serial bus system (15) can be read / written with the computer connected thereto through its connection bus (6), if necessary through the electronics (10, 11) of the interface unit (9), which interface unit 25 (9) can also transmit independently or receive data at desired time intervals to / from the channels of the digital telephone or transmission network (13). System according to claim 6, characterized in that the interface unit (9) has its own processor (12) and bus (17) for automatically establishing contact through the channels in the digital telephone network interface (G) with the digital telephone network or transmission system. and to provide a time interval connection in the serial bus system (15) for these contacts, and that the interface unit (9) has an interface circuit system (10) and / or II a "17" J f dual port memory (11) for transmitting information about the function of the contact between the computer and the processor (12). 8. A system according to claim 6 or 7, characterized in that the interface unit (9) has external interfaces for devices which cannot be directly connected to said computer, but probably to said network or transmission system. 9. System according to claim 8, characterized in that an external interface is formed by a telephone connection (A) to which is connected an analog telephone handset (20), the signals of which are adapted to the digital telephone network in the interface unit. System according to any one of claims 6-9, characterized in that the interface unit (9) has external interfaces which emulate some of the external interfaces (E, F) used by the computer and / or its program. System according to any one of claims 6 - 10, characterized in that the interface unit (9) has one or more connectors (C1), thanks to which the electronics and / or program of the interface unit can be expanded with one or more expansion boards (26). with connection to any such network or transmission system (13b), to which the interface unit (9) itself does not have a connection. System according to any of claims 6 - 11, 25, characterized in that the interface unit (9) consists of a circuit board which can be installed in an extension connection in the computer bus (6).