AU708092B2 - A multi-user telephone arrangement - Google Patents

Description

Technical Field This invention relates to the provision of a telephone service in which two or more users may use one standard telephone and the charges for the calls can be recorded against the individual accounts of the users who made the corresponding calls.

One instance of where such a system may be of use is in university residential colleges where one phone may be provided for use by a number of students. Other areas of application include developing countries which are installing modern telephone systems, where multi-user phones could be provided in apartment buildings and other locations.

Background Art Party line systems are known from the time of manual exchanges when several subscribers were served by one exchange line, each subscriber having their own :t5 telephone subset.

Australian patent application No. 38513/93 discloses an enhanced telephone o9°o subset which can be programmed to provide quarantined use by each of several users. However such an arrangement requires a subset which has a considerable amount of processing power and is accordingly more expensive than a standard telephone, making it unsuitable for application in many of the situations for which the 9* present arrangement is intended. Furthermore the prior art subset does not provide means for discriminating between incoming calls to alert individual users.

Summary of the Invention This specification discloses a multi-user telephone arrangement including a telephone subset connected to an exchange via a telephone line, the exchange including a controller including a processor and associated memory, the memory including for each subscriber of the multi-user telephone a unique call accounting register, wherein each subscriber is allocated a unique multi-subscriber number including a line access prefix and a user code and a unique PIN stored in the memory and which enable access to the subscriber's call accounting register, wherein in making an outgoing call a subscriber sends his user code and PIN to the controller, and wherein the controller checks whether the user code and PIN are correct and if they are correct, the controller enable the subscriber to make an outgoing call, and charges the cost of the call to the subscriber's accounting register, and wherein, if the user code and PIN are incorrect, the controller does not enable the subscriber to make an outgoing call.

Brief Description of the Drawings The invention will be described with reference to the accompanying drawings, in which: Figure 1 is a block diagram of a multi-user telephone arrangement embodying the invention; Figure 2 represents the controller of Figure 1; Figure 3 is a flow diagram of the procedure for making an outgoing call; and Figure 4 is a flow diagram of the incoming call process.

Figure 5 shows a subscriber module of an exchange in which the invention °°may be used; Figure 6 shows details of the line interface circuit of Figure Figure 7 shows the setting up of a call.

Description of the Invention Figure 1 illustrates a telephone subset 1 connected to a line unit 2 of an exchange. The exchange is of the stored program control type, such as Alcatel's S.12 exchange which was described in Electrical Communication V.56, No. 2/3, 1981, published by ITT. The S.12 was then known as System 1240. However the invention may be applied in any other stored program control exchange.

The exchange includes a switch 3 and trunk unit 4 connecting the exchange to the telephone network. A controller 5 is connected to the line unit 2, switch 3, and trunk unit 4. The controller 5 is capable of receiving information on the line condition from line unit 2 and of monitoring signals sent from the subset 1 to line unit 2. The controller 5 is also arranged to send signals to the line unit 2 to enable the subset 1 to establish a call through the exchange or to prevent a call from the subset 1 from being established. The controller 5 may also be arranged to send signals via the line unit 2 to the subset 1 to instruct a user on the procedure to use the phone. The signals may be acoustic signals such as beeps or tones, voice signals, or signals to cause a message to be displayed on a display at the subset 1 if such a display is provided.

The controller 5 is shown in more detail in Figure 2 and includes a processor 21, and associated memory 22 and local communication interface 23.

The telephone company is able to record details of the users of each multi-user subset in the memory via communication interface 23. Each multi-user subset is assigned for each registered subscriber, a multi-subscriber number which includes a prefix denoting the access line followed by a subscriber code including one or more digits denoting the individual subscribers authorized to use the subset. In this way the exchange can record individual billing information for each subscriber. Information oo:. 5 on each subscriber's credit status can be entered into memory via the local communication interface 23. Information recorded for each user of a multi-user telephone may include a personal identification number (PIN).

The operation of the multi-user telephone arrangement will now be described.

The making of an outgoing call is illustrated in the flow diagram of Figure 3.

Initially the user lifts the handset and this causes the subset 1 to close its hook-switch.

The line unit 2 detects the closure of the hook-switch and this information is passed on to the controller 5. Controller 5 recognizes that the subset 1 connected to line unit 2 is a multi-user subset from details of the class of line stored in the exchange's memory and initiates a routine to establish the call set up. The controller 5 causes the signal generator means 6 to send a request to the user to enter, the user's code and PIN. Preferably, this request is a voice message but it may also be in the form of tones or beeps in which case written instructions should be provided at the subset 1 to enable the user to interpret the instructions. Alternatively, if the subset 1 is provided with a display, the instruction may cause an appropriate message to be displayed.

The subset 1 transmits the user code and PIN entered by the user to the exchange and the controller 5 checks that these are correct. The user code is used by the controller 5 to identify the account to which the call is to be charged, and the PIN provides authorization to charge the call to that account.

If the controller 5 finds that the PIN does not correspond to the user code, the controller 5 refuses access to the user to make the call. Alternatively the controller may send a message to the user advising of an incorrect code and requesting the user to re-enter the user code and PIN. After a predetermined number of failures, the controller 5 denies access to the call.

When the user code and PIN are correctly entered the controller 5 gives the subset 1 access to the exchange switch so that the subscriber can make a call by dialling the number in the normal way. The charge for the call is recorded against the subscribers account in the normal way.

Alternatively, when the user code and PIN are entered, the controller 5 may be programmed to check whether there is available credit in the subscribers account or whether the account is approaching a credit limit. If there is available credit, dial tone is provided to the subset 1 and the call is set up in the normal way. If the account is approaching a credit limit, the subscriber is notified before the call is set up. If the credit limit is exceeded, the subscriber may be denied access to make outgoing calls but still be able to receive incoming calls.

When the controller 5 grants access, dial tone is provided to subset 1 via line unit 2 and the subscriber dials the wanted number and the call proceeds as normal.

If the call is not established, busy tone is sent to subset 1. If the call is established, the controller 5 charges the cost to the subscriber's account.

On completion of the call the user hangs up, the subset 1 opens the line loop, and the exchange releases the call.

The procedure on receipt of an incoming call will now be described with the aid of the flow diagram of Figure 4.

A person wishing to make a call to a subscriber of a multi-user telephone dials the subscriber's unique multi-subscriber number which includes the line access number and the subscriber's user code. The controller 5 uses the user code to access stored information concerning the subscriber which identifies a ring signal code which is specific to the subscriber of the multi-user telephone.

The controller 5 causes the ring signal generator 8 to generate the ring signal code which is a distinct combination of ring signal bursts. In this way, subscribers who are familiar with their ring signal bursts are able to identify incoming calls intended for them and to ignore incoming calls intended for other subscribers.

An embodiment of the invention will be described in relation to an Alcatel S. 12 exchange with reference to Figures 5, 6 and 7.

The Alcatel 5.12 exchange utilizes a distributed processing architecture which is described in an article entitled "ITT 1240 Digital Exchange Architecture" in V.56, No.

2/3, 1981 Electrical Communications 126. Distributed processing adopts the practice of providing processors at various levels throughout the exchange appropriate to carrying out functions at those levels, rather than relying on a central processor. However the invention is also applicable to central processor exchanges.

S.The Subscriber Modules which interface subscribers to the exchange are described at page 222 Figure 5 of this patent specification reproduces Figure 6 of the :.t1 article illustrating the subscriber modules.

Each Subscriber Module 50 includes 60 analog line interface circuits 51 in two groups of thirty. A codec 52 is connected to each line interface circuit, and each group is multiplexed via multiplexer 53 into a terminal interface 54 in the terminal control element (TCE) 59.

The terminal control element includes a microprocessor 55, memory 56 and terminal interface 54 connected by a high speed bus Processor 55 is also connected by low speed bus 61 to line interface circuits 51 and ringing circuit 57. Processor 55 and associated memory 56 are described on page 137 of the journal.

Figure 6 reproduces Figure 7 at page 222 of the journal illustrating detail of the line interface circuit.

Line feed and supervision, ring injection, and test points are illustrated at 62.

A high voltage interface 63 isolates the exchange from high voltages which may be picked up by the phone line. Interface 63 feeds into a transmission interface 64 which performs such functions as buffering receive and transmit analog signals, two/four wire conversion, decoding logic for control interface, etc. Interface 64 is connected to codec/filter 52.

A line common function circuit 65 is connected to processor 55, interface 64 and codec 52, to convert processor instructions into functional instructions to control the operation of the circuits, and to transfer outputs from the circuits to the processor.

Line feed and supervision circuit 66 is connected to the line and high voltage I/F 63 and transmission interface 64.

Figure 7 reproduces Figure 15 on page 229 of the journal, showing setting up of a local call.

When the subscriber lifts the handset 71, the TCE 59 is alerted to this via the subscriber module 50. TCE 59 identifies the calling line and transmits a message containing the calling line identity and request for line seizure to a first auxiliary control element (ACE) 72 via digital switch The first ACE 72 is a call control ACE and has a structure generally similar to that of TCE 59. However ACE 72 may have larger than the memory 56 of TCE 59.

The memory of ACE 72 may contain detailed information relating to a large number of subscriber lines such as the line of subscriber 71. The subscriber information stored in the memory of ACE 72 may include the class of service of the subscriber and o other details such as the subscribers billing information and PIN in the case of a multiuser telephone of the present invention.

Call control ACE 72 sends a request to system ACE 73 to prepare a connexion to a suitable receiver. ACE 73 selects a receiver and sends its identity to the TCE 74 of a service circuits module 75 with an instruction to connect the receiver to the calling line. Service Circuits module TCE 74 enables the selected receiver and initiates dial tone sending and sets up a path to calling TCE 59. According to our invention TCE 74 may cause a non-standard dialling tone or voice message to be sent to alert the user that the phone is a multi-user phone and that he must enter the required identification codes. Service circuits module performs various functions as described on page 225 of the journal.

Calling TCE 59 then sets up a path to service circuit module TCE 74 to enable the dialling signals to be sent to TCE 74. When the user enters the user code and PIN these are received in the receiver of the service circuits module and relayed to call control ACE 72 which carries out a validation check, and credit check if applicable. If the call control ACE 72 accepts the user code and PIN, an instruction is sent to the service circuits module TCE 74 to cause a standard dial tone or voice message enabling the user to dial the wanted number. The call then proceeds in the normal manner.

Preferably, the multi-subscriber user code and the ring pattern are in a fixed relationship to simplify the process of selecting a ring signal at the exchange.

In a further option, an extended version of call completion to busy subscriber is proposed, to improve the efficiency of calling on the heavily used multi-user access lines. Under this scheme, when a caller encounters busy, he invokes CCBS using normal procedures. When the called access becomes free, the called exchange signals this back to the calling exchange. If the original calling access is then available, then normal call completion to the busy subscriber proceeds normally.

If on the other hand, the original calling access is now busy (this will often be the case, with multi-user access), the original calling exchange now enters surveillance 0 of the local access. When it becomes free, the originating exchange signals back to r* r the originally called exchange (over the still active TCAP dialog). If the destination is now free, the CCBS can proceed. If on the other hand, the destination is now busy, then access monitoring activity returns to the destination exchange. This 'ping-pong' CCBS will be required to guarantee a high degree of successful completion of calls on heavily used accesses. The time that such a procedure can be active can be limited, eg. to one hour. Terminating calls under CCBS may be given priority over originating calls, to improve call completion rates, and clear backlogs of booked calls.

The claims defining the invention are as follows: 1. A multi-user telephone arrangement including a telephone subset connected to an exchange via a telephone line, the exchange including a controller including a processor and associated memory, the memory including for each subscriber of the multi-user telephone a unique call accounting register, wherein each subscriber is allocated a unique multi-subscriber number including a line access prefix and a user code and a unique PIN stored in the memory and which enable access to the subscriber's call accounting register, wherein in making an outgoing call a subscriber sends his user code and PIN to the controller, and wherein the controller checks whether the user code and PIN are correct and if they are correct, the controller enable the subscriber to make an outgoing call, and charges the cost of the call to the subscriber's accounting register, and wherein, if the user code and PIN are incorrect, the controller does not enable the subscriber to make an outgoing call.

2. An arrangement as claimed in claim 1 wherein, before enabling the subscriber to make an outgoing call, the controller checks the credit status of the subscriber's accounting register and enable the subscriber to make an outgoing call only if the accounting register is satisfactory.

3. An arrangement as claimed in claim 1 or claim 2 wherein when the subscriber's subset goes OFF-HOOK, the controller sends a signal to the subscriber to enter the subscriber's user code and PIN.

4. An arrangement as claimed in any one of claims 1 to 3 wherein, if the user code and PIN are not correct, the controller sends a signal to the subscriber requesting that the user code and PIN be re-entered.

An arrangement as claimed in claim 4, wherein if the user code and PIN are re-entered incorrectly a predetermined number of times, the controller denies access for the call.

6. An arrangement as claimed in any one of claims 1 to 5 wherein the controller checks the subscriber's accounting register contents against a credit limit and advises

Claims (3)

1. 7. An arrangement as claimed in any one of claims 1 to 6 including a controllable call signal generator able to generate a plurality of distinct call signals, and wherein the controller allocates a distinct call signal to each of the multi- subscribers.
2. 8. An arrangement as claimed in any one of claims 1 to 7 including a call completion to busy subscriber routine which is adapted to monitor either the calling line or the called line depending on the busy status of the calling and called lines.
3. 9. A multi-user telephone arrangement substantially as herein described with reference to the accompanying drawings. DATED THIS TWENTY-THIRD DAY OF AUGUST 1995 1 ALCATEL AUSTRALIA LIMITED e:o 000 005 363) **ee S ABSTRACT A standard telephone subset is connected to a stored program controlled exchange which is programmed to recognize each of several different users on entry of individual user codes via the keypad when a user wishes to make an outgoing call. When a user wishes to make a call, he lifts the handset and the exchange sends a coded dial tone or voice message advising the user that the telephone is a multi-user telephone and that the user must enter a user code. The exchange processor is programmed to verify that the user code which S includes user identification and user PIN numbers is valid to verify the user's credit o°°o status. The user code enables the exchange to charge the call to a specific account associated with the user. When the exchange processor has verified the validity of the user code and the user's credit status, the exchange provides dial tone to enable the see user to make a call. S.. °oIo *o•@o oo S SO S S.oo