AU609285B2 - Process for a computer-controlled switching device in particular a key telephone exchange, in which data terminals and telephone terminals can be alternatively connected - Google Patents

Abstract

A key telephone terminal (T1) connected via a four-wire line (useful connection a, b and control connection c, d) to the exchange (VE) is also connected to a subscriber line (ATn), in addition to a data terminal (fax, PC). Since when a request for a connection comes from such a device, an indication occurs both on the useful connection and on the control connection but when a data terminal is connected, an indication only occurs on the useful connection (a, b wire), the system can tell whether a data communication or a normal communication exists. If a data communication is recognised, a temporary data protection is put into effect during the period of time of data transmission. Thus, the relevant subscriber connection is blocked for particular service features which can be activated by the system or by another subscriber (for example call insertion, call waiting and intrusion). Follow-up functions of manipulations at the key telephone terminal which are transmitted via the control connection are also suppressed during the existence of the temporary data protection. <IMAGE>

Description

1 li "1 111 4LAA/Vl/XiI±)dUL NYVI)iIlU~idJj ijV 'id OL 1.25I 111.-11 1111 i 1 9285 F Ref: 90724 S F Ref: 90724 FORM COMMONWEALTH OF AUSTRALIA PATENTS ACT 1952 COMPLETE SPECIFICATION

(ORIGINAL)

FOR OFFICE USE: Class Int Class Complete Specification Lodged: Accepted: Published: Priority: Related Art: 'i [.is do -nt c..n ai.: sice amendments made vnd :r Section ~9i ad is correct for printing Name and Address of Applicant: Address for Service: Siemens Aktiengesellschaft Wittelsbacherplatz 2 0-8000 Munich 2 FEDERAL REPUBLIC OF GERMANY Spruson Ferguson, Patent Attorneys Level 33 St Martins Tower, 31 Market Street Sydney, New South Wales, 2000, Australia S Complete Specification for the invention entitled: Process for a Computer-Controlled Switching Device in Particular a Key Telephone Exchange, in which Data Terminals and Telephone Terminals can be Alternatively Connected The following statement is a full description of this invention, including rhe best method of performing it known to me/us 5845/3 i I II~ -In-

I

Procass- for aa-mviter-.cntroledcewitchi particular a key telephonexeha ge, in which data terminals and lepnone terminals can be alternatively e \d The invention relates to al e for acomputer-controlled switching device, in which a telephone terminal and furthermore a data terminal can be alternatively connected, the latter directly or via a modem for the sending or for the reception of data signals, to at least one branch line connecting the respective terminal to the switching device, in particular for a so-called key telephone exchange, with a control computer unit which executes all switching functi.ons and featurespecific functions and has access to memory arrangements, .in which the control data necessary for this are stored and in which, for the connection of the key telephone terminals, in addition to the useful connection serving essentially for the transmission of the voice information, there is provided a control connection to the switching device, via which, inter alia, the information signals concerned with the call setup and call clear down are transmitted.

Such modernly designed switching devices are not only made capable of actual switching control, but also of a control or realisation of additional control operations above and beyond the actual call procedure. Such additional functions are generally referred to as feac 'tures, and a large number of very different features are known. Such features may either be initiated when seizing the switching device or else during an already existing call. This can take place for example by dialling certain numbers or number sequences or by the actuation of so-called function keys. Certain features are dependent oil the type and functional scope of the terminals used.

Apart from realising the said useful connection and the separate control connection by one pair of wires in each case, these can also be realised separated by i N^f*^ 2 different positions in time physically on the same transmission medium, for example a two-wire subscriber branch line.

Via a common subscriber line unit, a branch line can be connected both to a telephone terminal and to a data terminal for data transmission on the telephone lines. Consequently, for example fax messages can be sent and received or it can serve as a data terminal in connection with a modem, a terminal unit or a personal computer. The call setup necessary for data transmission can take place with the telephone terminal assigned to the data terminal via the common branch line. In order to avoid interference during data transmission due to operating sequences of the switching device in conjunction with telephone operation, permanent restrictions in the scope of features are to be provided in the case of connections of the said type for the voice mode of communication. It would also be possible to couple the data terminal directly to an exchange line. This would have still further restrictions as a consequence. For voice traffic, the exchange line concerned could only be used for so-called outgoing calls.

It is the object of the invention to specify a process for a switching device with the features mentioned at the beginning in which both the interference of a data transmission is avoided and the resultant restrictions for the voice mode of communication are reduced.

In accordance with the present invention there is disclosed a method of preventing interruption to data communications in a communication system, said system comprising a computer-controlled switching device to S which at least one telephone terminal or a data terminal is connected via one of a plurality of branch lines, each of said branch lines comprising a signal connection for connection to a telephone terminal or data terminal associated with said branch line and a control connection connecting to said associated telephone terminal, a signal connection status of each of said branch lines being determined by a connecting unit which communicates said status for evaluation by a controlling computer unit which is adapted to execute all switching functions of said system in concert with a memory section adapted to store control data necessary for implementing predetermined switching and feature-specific functions of said system, said control connections being connections via which said predetermined functions are actuated from said telephone terminal, said method comprising the steps of: TMS/1113o -3using said connecting unit to detect when data transmission as opposed to voice transmission is being carried over a particular signal connection and thereby, via said computer unit, isolate the corresponding control connection to thereby prevent normal operation of the corresponding telephone terminal and thus providing temporary data protection through preventing interference with said data transmission.

Further advantageous developments of the invention are to be taken from the remaining subclaims.

A preferred embodiment will now be described with reference to the Figure. The Figure shows a diagrammatic representation of a telephone exchange VE, to which subscriber terminals T1...Tn are connected in star form. In the exemplary embodiment, voice transmission is to take place in analog mode. For the connection of the key terminals, a four-wire branch line is used, c s C t tc Jt 11 4 which in each case consists of a pair of speech wires a/b, representing the useful connection, and a pair of signalling wires c/d, representing the control connection. In the case of an exclusively digital switching system, the control connection and the useful connection provided for the transmission of voice information could be realised on a two-wire branch line, in which case at least one useful channel and one control channel could be formed for each terminal by a certain position in time.

By means of a changeover device U, instead of the key telephone terminal TI, connected by four wires to the switching device, a data terminal DE can be connected to the speech wires al/bl. The terminals TI...Tn or DE are connected via a connecting unit AT, which includes inter 15 alia the call connection and the indication of the a/b line loop, to an electronic coupling device KN. For lines ALI...ALx, leading to a public exchange, this takes place in each case via an assigned connecting unit AS.

This includes, inter alia, a contact usi, which lies in the exchange circuit isolated by a transformer Ve from the switching matrix.

The control tasks of the switching device VE are assumed by the central control computer unit ZSt, which is coupled to the said units AT and AS and the other system components, such as for example the coupling device KN, a unit MZ serving for the formation of the multi-frequency code signals and a unit HZ, responsible SK for the generation of the call progress tones. Such a coupling exists furthermore between this control computer unit and a processing unit Ve, which is assigned to each pair of signalling wires c/d and contains a transmit section S and a receive section E. With inclusion of the processing unit Ve, a two-way information transmission can be performed via the signalling wires c/d between a key telephone terminal T1 and the control computer unit ZSt. For example, the information transmitted from the control computer unit ZSt to the telephone terminal T1 via the signalling wires c/d can be sent by a binary voltage modulation and the information to be transmitted in the opposite direction can be sent by a binary current modulation. With the latter, for example the actions performed on the respective terminal, such as for example the actuation of individual keys TS, are then signalled.

This is to take place for example in conjunction with the control unit Pe through the unit IR. The information bits occurring on the respective signalling wires c/d in the opposite direction due to the voltage modulation provided are registered in cooperation with the unit UD by this control unit Pe. They may, for example, concern setting information for optical display elements LF or for a display A. The voice information is transmitted via the respective pair of speech wires a/b.

The speech circuit Sp is connected to these speech wires a/b. It serves in conjunction with the handset HA for the processing of the transmitted voice information and forms the line termination.

~The criteria emitted by a key telephone terminal T1 are sent via the signalling wires cl/dl, while the criteria emitted by a data terminal DE are sent exclusivr ely via the useful connection, i.e. in the exemplary embodiment via the pair of speech wires al/bl. Similarly, in the case of a normal telephone terminal cornnected merely by means of a two-wire branch line, for example telephone terminal Tn, the transmission of the criteria produced for example during call setup and during call clear down is exclusively performed via the pair of wires an/bno The basic structure of such a switching device is known. There is consequently no need to give details of the circuitry or describe the operations involved in a call setup and call clear down. It should also be mentioned that the central control computer unit ZSt has access to the data stored in a memory device SE. These relate, inter alia, to the entire system program stored in the memory P and to the technical operating data associated with it and contained in a main memory M. The customer data are stored ii a memory section KD. This data includes for example the abbreviated dialling custmerdataarestord ii a emoy setio RD. Thi j i( -6numbers provided for the switching device and authorisations allocated to the individual subscriber terminals T1, Tn. Thus, the features to be utilised by individual subscribers are also stored therein. The configuring of the data contained in the customer data memory KD can take place for example via the input keyboard of a terminal which can be specified as operating terminal.

A data transmission in outgoing and incoming direction can also be performed on the pair of speech wires a/b (useful connection) of a four-wire branch line ATn, by means of which the key telephone terminal T1 is connected to the switching device VE. For this purpose, the telephone terminal T1 is assigned a data terminal DE.

This data terminal may, for example, be a fa:1 device. If a connection is to be established from such a fax device to a corresponding partner device, with inclusion of the switching device VE, via a line All, the setting up of f this connection can take place in the same way as the setting up of a telephone call by a subscriber by means of the assigned parallel device TI. The commands produced for this purpose are fed to the central control computer unit ZSt via the control connection, i.e. via the signalling wires cl/dl. Thus, for example the removing of the handset and the emitted dialling numbers are transmitted via this connection. Once the receiving device has signalled its readiness to receive by a corresponding acknowledgement tone, the data transmission can be initiated as known by the actuation of a data transmission key DT. The relay UM, associated with the changeover device U, is set so that, via its contacts lum and 2um, the wires al and bl are disconnected from the telephone terminal and changed over to the fax device DE.

This takes place within such a short time that the connection set up is not released. The changeover device U, which is also to be designed as a purely electronic Sunit, may also be a subunit of the data terminal DE. The criteria exchange performed after the loop formation between the interconnected data terminals before the actual data transmfission takes place exclusively via the 7 pair of wires al/bl. This is detected by a corresponding indication by the central control computer unit ZSt. The criteria occurring on the wires al and bl are registered by the control computer unit through an indication unit contained in the connecting unit AT. In conjunction with the stored information that the connection concerned leads both to a telephone terminal and alternatively to a data terminal, the effective connection of the data terminal can be established. In the case of a call connection, the criteria exchange would namely take place, as already mentioned, via the wires cl and dl, so that in such a case the control computer unit can detect the type of terminal via the processing unit Ve. If, for r ,t example, the switching device is designed as a hybrid key 15 telephone system, both four-wire key telephone terminals to be connected and normal telephone terminals to be connected by two wires can be connected as desired as call terminals to the individual ports. This then presupposes that an indication takes place in any event for the wires a and b. In the case of assigning a data terminal to a telephone terminal to be connected by four wires, the connection of a data terminal can then be determined in the same way as its disconnection without additional measures, as already described. This makes it possible that a temporary data protection can be performed by the control computer unit ZSt. It is thus ensured that all requests made by the system or by another subscriber which would have as a consequence, for example, the switching of tones to the relevant speech wires a and b, are ignored until completion of the data transmission. Thus, during such a data transmission, the connection concerned is protected for example against internal call waiting and against external call fade-in and against trunk offering. Call fade-in takes place for example whenever there is a call for a telephone terminal in the engaged state on the external line assigned to it.

Furthermore, the actions performed on the assigned key telephone terminal T1 in the state of such a temporary data protection, that is for example the lifting of the lli i, i i 8 handset or the actuation of keys, is not taken into consideration. So during the times in which no data transmission is taking place, these said features can be requested with respect to the assigned telephone terminal. The state of an activated temporary data protection can be displayed by the control computer unit via the processing unit Ve on the telephone terminal, for example on a display A. The information necessary for this is fed to the telephone terminal T1 via the signalling wires c and d, so that a data transmission is not affected as a result.

If, once he has actuated the key DT signalling the start, the subscriber has replaced the handset before the end of the fax transmission, the entire connection is 15 cleared at the end of the data transmission which is performed. If, however, the handset remains removed and the fax transmission is completed, the connection is still not released, so there is the possibility of a subsequent call.

If there is no key DT on a data terminal, a key of the telephone terqinal T1 may also be programmed for this function. In .der to ensure that in such a case the transmission of the changeover signals concerned takes place, additional control measures have to be taken. It is also possible to set up the data connection directly from the data terminal by dialling by means of an automnitic dialler. After changing over by the changeover device U, the control computer unit detects in the same way as already described, on the basis of the dialling information sent via these speech wires, that data traffic is concerned. In the case of a call leaving the telephone terminal TI, this dialling information would namely be delivered via the signalling wires cl/dl.

Once it has been detected that the connection in coming from a data terminal, the temporary data protection is automaticaliy activated.

In the case of an incoming call, the call is first of all signalled both on the telephone terminal T1 and on the data terminal DE. After a certain call 9 sequence, the changeover to the data terminal is carried out by the call evaluation RA in the data terminal DE, by actuation of the relay UM. The line loop subsequently formed and the criteria exchange performed between the interconnected fax devices is in turn detected in the switching device. This then leads to the activation of the temporary data protection, so that certain features which are accompanied by an interference of the data transmission cannot be requested during the time of data transmission.

Instead of a fax terminal, a terminal unit or a personal computer could be connected as data terminal DE.

f .This then requires the connection of a modem MO via a 4 suitable interface, as is indicated in the Figure by the C r 15 unit in broken lines. The changeover device U could then represent a subunit of the modem MO. After the changeover of the wires a and b to the modem, the temporary data protection can then be initiated on the basis of the I criteria transmission performed via these wires during data traffic, in the same way as described for the data S c transmission with a fax terminal.

With the criterion of temporary data protection, in the case of a central charge registration a selective set of data could be output for the respective data call section, as a result of which an assignment of the charge pulses received to data calls or voice calls is possible.

The data stored in a central charge registration device GZ can be printed out by means of the printing device Dr.

In the case of a different type of charge registration, two separate summators can be used, namely the counter ZS provided for the addition of charge pulses occurring in the case of a voice call and the counter ZD provided for the addition of charge pulses occurring in the case of a data call. Thus, a separate call data registration cpn be performed in a simple way. The associated counters may be assigned directly to the switching device VE.

I The counter reading can be sent on request by a subscriber to his telephone station and displayed there, for example on the display A provided.

Claims (13)

1. A method of preventing interruption to data communications in a communication system, said system comprising a computer-controlled switching device to which at least one telephone terminal or a data terminal is connected via one of a plurality of branch lines, each of said branch lines comprising a signal connection for connection to a telephone terminal or data terminal associated with said branch line and a control connection connecting to said associated telephone terminal, a signal connection status of each of said branch lines being determined by a connecting unit which communicates said status for evaluation by a controlling computer unit which is adapted to execute all switching functions of said system in concert with a memory section adapted to store control data necessary for implementing predetermined switching and feature-specific functions of said system, said control connections being connections via which said predetermined functions are actuated from said telephone terminal, said method comprising the steps of: using said connecting unit to detect when data transmission as opposed to voice transmission is being carried over a particular signal connection and thereby, via said computer unit, isolate the corresponding control connection to thereby prevent normal operation of the corresponding telephone terminal and thus providing temporary data protection through preventing interference with said data transmission.

2. A method as claimed in claim 1 wherein said switching device is S a key telephone exchange.

3. A method as claimed in claim 1 or 2 wherein a modem is provided to interconnect said data terminal with said signal connection.

4. A method as claimed in claim 1, 2 or 3, wherein the prevention of normal operation of said telephone terminal involves the blocking of features which normally apply acoustic signals to the signal connections. S'

5. A method as claimed in any one of the preceding claims, wherein for each said branch line, the signal connection and the control connection are in each case realised by a pair of wires.

6. A method according to any one of the preceding claims, wherein for the registration of coomunication fees, fee pulses that arrive during TMS11113o 11 the time of an established connection with said telephone terminal or data terminal, are registered, and a common registration unit is provided such that those fee pulses arriving during a data transmission are provided with an additional code so that a separate printout of fees incurred during a data connection or a normal speech connection can be made.

7. A method according to any one of claims 1 to 5, wherein for the registration of communication fees, fee pulses that arrive during the time of an established subscriber connection are registered in a first summing counter for a connection of a telephone terminal or in a second summing counter for a connecting of a data terminal.

8. A method according to any one of the preceding claims, whereby, for communications originating within said system, the changeover of the respective signal connection from the associated telephone terminal to the associated data terminal takes place after an appropriate connection setup performed by actuation of the associated telephone terminal followed by the actuation of a corresponding data transmission key wherein the temporary data protection is effected on the basis of information delivered via the connecting unit to the computer unit.

9. A method according to any one of claims 1 to 7, whereby, for communications originating within said system, the connection of the data terminal to the associated signal connection is implemented directly upon the automatic emission of dialling information from the data terminal wherein the temporary data protection is effected by the correspondingly evaluated status information established on the signal connection with the dialling informatick, by the control computer unit.

A method according to any one of the preceding claims, wherein during operation of the data terminal on a signal connection, the corresponding control connection is disabled thus preventing erroneous data transmission upon actuation of the corresponding telephone terminal, the disabled status of the control connection being displayed on a display of the telephone terminal.

11. Apparatus adapted for use of the method as claimed in any one of the preceding claims. TMS/1113o xl 12

12. Apparatus substantially as described herein with reference to the drawing.

13. A method substantially as described herein with reference to the drawing. DATED this THIRD day of JANUARY 1991 Siemens Aktiengesellschaft Patent Attorneys for the Applicant SPRUSON FERGUSON j 41 M 1 TMS/1113o