Such a system is already known in the art. e.g. from the published PCT application W086/03915. This system includes a plurality of payphone stations operating with magnetic cards and each having a message generating means including a keyboard. By means of this keyboard a user of a payphone station may for instance key a message, constituted by the subscriber number of a telephone station, to initiate a voice communication with this telephone station, this communication being established through the switching exchange.

To be noted that this communication is only established when the magnetic card is valid. This validity is checked under the control of a central computer performing functions in common for the plurality of paystations.

It is a general object of the present invention to enlarge the application domain of a payphone system by providing new services to the users thereof.

According to the invention this object is achieved due to the fact that it further includes transcoder means coupled to said message generating means and able to convert said messages which are in an alphanumerical text

code into messages in a second code and at least one second station coupled o said transcoder means, said second station operating with said second code messages.

Another characteristic feature of the present invention is that said second station is a facsimile station and said second code is a facsimile code which is a representation of a graphical form of said alphanumerical text code .

In this way the payphone system is able to generate facsimile code messages by the cooperation of the message generating means and the transcoder means. These messages may then be transmitted to a facsimile station and advantageously by providing the transcoder means in common for a first plurality of paystations and for a second plurality of facsimile stations.

The above mentioned and other objects and features of the invention will become more apparent and the invention itself will be best understood by referring to the following description of an embodiment taken in conjunction with the accompanying drawings wherein :

Fig. 1 is a schematic diagram of a first embodiment of a payphone system according to the invention;

Fig. 2 is a schematic front view of the housing of a payphone PP whose main constituent electronic parts are shown by blocks in Fig. 1.

Fig. 3 is a schematic diagram of a second embodiment of a payphone system according to the invention.

The payphone system represented in Fig. 1 includes a communication switching exchange N to which are coupled a plurality of magnetic card controlled payphone stations, telephone subscriber sets and facsimile stations, such as PP, SS and FS respectively, as well as an authorization center AC and a card administration office CA.

The coupling of PP, SS, FS and CA to the telecommunication switching exchange N is done via

terminals LI, L4, L2 and L5 respectively, whilst AC is coupled to a set of terminals L3 which all have the same subscriber number. When this number is called the communication exchange will automatically search for a free terminal out of the set in the same way as for PABX line hunting.

The magnetic card controlled payphone station PP includes in its housing an AC to DC converter (not identified), a processor MP which is coupled to a magnetic card reader R, a display unit D, an alphanumerical keyboard K, a set of programmable function keys F, a telephone circuit T and a modem MD. The telephone circuit T is coupled to the switching exchange N via the terminal LI as well to a telephone handset H and to the modem MD for transmitting and receiving data. The converter operates from the AC mains voltage to supply a suitable DC voltage to the various elements of PP.

A portion of the elements H, D, K, F and R is visible on the front side of the housing of PP, as represented in Fig. 2. This housing further has a card slot CS.

The telephone circuit T is adapted to perform the usual telephone functions, such as two-to-four wire conversion, dial tone detection, dial pulse or Dual Tone Multi-frequency Signalling (DTMF) transmission, metering pulse detection, as well known in the telephone art.

The processor MP is able to scan the keys of the alphanumerical keyboard K and the programmable function keys F and to drive the display D. MP, K, F and D together constitute means to generate in the payphone station messages in an alphanumerical text code, e.g. ASCII code. The processor MP also controls the modem MD and together they are able to transmit the above alphanumerical text code messages to the switching exchange N. The processor MP further processes data provided by

the magnetic card reader R and controls the operation of telephone circuit T.

The credit card administration office CA is the computer center of a credit card company managing the credit card accounts. A plurality of such offices may be provided.

The facsimile station FS operates with a facsimile code, e.g. CCITT G3 code.

The authorization center AC includes a computer PC which is coupled to a common transcoder TR, to a plurality of modems M having access to the switching exchange N and to a storage unit S which memorizes a black list of unauthorized card numbers. The transcoder TR is able to convert the above alphanumerical text code to the above facsimile code. Modems M together with computer PC are able to receive the above alphanumerical textcode messages from switching exchange N, and to transmit these messages to the exchange after conversion by transcoder TR into facsimile code messages. The above described telecommunication switching system operates as follows when a voice communication has to be established from the payphone station PP to the telephone subset SS.

A user of the payphone station PP introduces his magnetic card in the card slot CS and then selects the option "voice call" by means of one of the programmable function keys F. As a consequence a communication path is then established between PP and the authorization center AC and more particularly between the modem MD in PP and one of the modems M in AC. The card number read from the card by the reader R is then transmitted to the center AC where it is checked against the black list stored in the unit S under the control of the computer PC. As a result either an authorization signal or an inhibition signal is transmitted to the payphone station PP and in both cases

the communication path is afterwards released. Upon the receipt of an inhibition signal in PP the call can no longer proceed, whereas upon the receipt of an authorization signal the user can proceed with the voice call by keying the destination number, e.g. of the telephone subset SS. When SS is free a conversation can take place.

In case the user of the payphone PP wants to make a "facsimile call" to a facsimile station, e.g. to FS, he introduces his magnetic card in the card slot CS and presses the appropriate programmable function key of the set F. As a consequence the switching exchange N establishes a first communication path between PP and the authorization center AC and more particularly between the modem MD in PP and one of the modems M in AC. The user then keys a message on the keyboard K, edits it on the display D with the help of the function keys F, and finally keys the identity number of the facsimile station FS. The card number, the message in text code and the above identity number are then transmitted as a message along the above first path to the center AC where the card number is checked in the same way as described above for a voice call. In case the communication is authorized an "OK" message is sent back to the the payphone station and visualised on the display D. The first communication path is then released. Then the computer PC initiates the transcoder TR to convert the text code of the received text code message to a facsimile code message. Afterwards the switching exchange N establishes a second path to the facsimile station FS with the help of the above identity number and transmits the converted message to FS. Therein the message is printed out or is visualised in any other way. When the latter station FS is busy several retries are made. If the communication is not authorised a message is sent back to the payphone PP and visualised on the

display D to indicate to the user that the call cannot proceed. The first communication path is then released.

From the above it follows that N, MP, MD, PC, M constitute means to establish a first data communication path via the exchange N and between P and the transcoder TR to transmit text code message therethrough, and to establish a second communication path via the exchange N and between the transcoder TR and the facsimile station FS. At regular times AC delivers invoices for the different credit card companies by setting up automatic calls to the card administration offices such as CA and transmitting the billing information. These calls are set up under the control of the computer PC which stores in its memory the fixed subscriber number of the administration offices.

Fig. 3 shows an alternative embodiment of a payphone system according to the invention. As in Fig. 1, it includes a communication switching exchange N to which are coupled payphone stations such as PP via terminal LI, an Authorisation Center AC via a bundle of terminals L3, a Card Administration center CA via terminal L5 and a telephone subscriber set SS via terminal L4. It further includes a telex exchange X to which the Authorisation Center AC and a Telex Station TS are coupled via a bundle of terminals L6 and via terminal L2 respectively. The terminals of bundle L6 are coupled to a plurality of line circuits LC also coupled to the computer PC. In this embodiment, the alphanumerical messages keyed in payphone station PP and having TS as a destination are transmitted to AC, converted by the transcoder TR to telex code messages (e.g. Baudot code) and transmitted via one of the line circuits LC via the telex exchange X to the telex station TS where they are printed out. This happens in a way similar to that described above in relation to Fig. 1. While the principles of the invention have been

described above in connection with specific apparatus, it is to be clearly understood that this description is made only by way of example and not as a limitation on the scope of the invention.