GB2123254A

GB2123254A - Telephone instruments

Info

Publication number: GB2123254A
Application number: GB08313429A
Authority: GB
Inventors: Grant Cameron Wilkinson; Harry Shutt
Original assignee: ANSWERCALL Ltd; General Electric Company PLC
Current assignee: ANSWERCALL Ltd; General Electric Company PLC
Priority date: 1982-05-14
Filing date: 1983-05-16
Publication date: 1984-01-25
Also published as: GB8313429D0

Abstract

A telephone instrument includes a microprocessor (10) preprogrammable from a keyboard (12) of the instrument with an authorisation level. The programmed authorisation level is used by the microprocessor (10) to determine whether a call to a telephone number "dialled" by use of the keyboard (12) is permitted. If a non-permitted number is dialled the microprocessor (10) causes a switch (19) to operate to disconnect the line (15,15%). Reprogramming of the authorisation level is prohibited until a key-operated switch (18) is closed. Repertory dialling facilities may also be provided by the microprocessor (10) in combination with a random-access- memory (R.A.M.) (11). Since calls to numbers held in the R.A.M. (11) are not subjected to prohibition, reprogramming of the repertory numbers is prevented unless either the key-operated switch (18) is closed or the preprogrammed authorisation level is such as to permit any outgoing call. In an alternative embodiment (not shown) a plurality of switches controlled by a key- operated lock are used to determine the authorisation level. <IMAGE>

Description

SPECIFICATION Telephone instruments The present invention relates to telephone instruments and more particularly, but not exclusively to such instruments including repertory dialling facilities.

It is now common practice for users of private branch exchanges which are connected to a public telephone switching network to have their telephones equipped with direct dialling out facilities. Thus calls may be made to telephones connected to the public telephone network without intervention of an operator.

In the absence of operator intervention there is no facility for monitoring the calls made from individual extension telephones. Thus there is no monitoring of the destination of telephone calls or of the duration of the calls.

Similarly, in domestic situations, there is no facility for the telephone authority's customer, the person who will be billed, to monitor every call made from a telephone for which he is responsible.

Previous methods of restricting telephone usage have involved the use of a personal identification code.

for example one such telephone instrument using identification codes is disclosed in United Kingdom Patent No. 1569257.

The telephone instrument of Patent No. 1569257 has only three modes of working namely an 'inhibit' mode in which all outgoing calls (with the exception of emergency calls) are based, a 'local' mode in which only local calls are permitted and a 'normal' mode in which any outgoing call is permitted.

Once authorised into either of the latter two modes the user has to remember to key in or dial another number to cancel the authorisation other wise the telephone remains available for use by unauthorised persons.

Another telephone instrument using identification codes is described in United Kingdom Patent application No. 8032590 (publication No. 2086187A) which similarly requires the user to operate a switch of the apparatus to cancel the authorisation but which has a slightly more flexible 'barring' system.

It is one object of the present invention to provide a telephone instrument having improved barring and/or security arrangements.

According to one aspect of the present invention in a telephone instrument of the kind having manually operable means arranged to cause the transmission to line of signals defining digits of a telephone number, means are arranged to store barring data in respect of each of a plurality of authorisation levels, which barring data determines for each of said authorisation levels which, if any, of a plurality of telephone numbers and/or codes are prohibited, means are arranged to permit preselection of an authorisation level from the plurality of authorisation levels and the instrument includes monitoring means responsive to said barring data and to the preselected authorisation level of the instrument to monitor signals transmitted to line in respect of a telephone call to determine whether a telephone number and/or code so transmitted is a prohibited number and/or code and, if so, to prevent further progress of such a call.

Preferably, said monitoring means is arranged to prevent further progress of such a call by preventing the transmission to line of a signal defining any subsequent digit of the prohibited telephone number and/or code.

Alternatively the monitoring means may be arranged to prevent further progress of such a call by causing disconnection of the line.

Preferably also, the barring data is alterable by use of the manually operable means of the instrument and a key operable siwtch is provided which is arranged to prevent authorised alteration of such data.

Alternatively, however, the barring data could be alterable by use of any other suitable means, such as, via the telephone line connected to another telephone instrument provided with a security facility, for instance, a key-operable switch.

The monitoring means may be arranged to remove the barring at any time at which the key operable switch is operated.

The instrument may include a repertory store programmable from said manually operable means with a plurality of telephone numbers which telephone numbers may include a barred code, the monitoring means being arranged to ignore barring if a repertory number is selected.

Reprogramming of the repertory store may be prohibited for certain ones of the preselected authorisation levels of the instrument. The prohibition may be overridden by the key operable switch.

The monitoring means may be a micro-processor.

In an alternative embodiment the authorisation levels are preselected by operation of a plurality of manually operable switches housed within the casing of the instrument, access to the switches being secured by means of a key operable locking mechanism of the casing.

Furthermore, the telephone instrument can include means arranged to disconnect the line if a call, which does not have a prohibited number and/or code, is in progress for longer than a permitted time, so as to prevent continuation of such a call.

According to a second aspect of the present invention in a telephone instrument of the kind having manually operable means arranged to cause the transmission to line of signals defining digits of a telephone number, means are provided for storing first data defining a plurality of telephone numbers and/or codes and for storing second data defining a permitted time in respect of each telephone number and/or code so stored and the instrument includes monitoring means responsive to said first data to determine from signals transmission to line whether a call is a restricted call and, if so, is responsive to said second data to disconnect the line if such a call is in progress for longer than the permitted time so as to prevent continuation of a said call.

Preferably the monitoring means isa microprocessorwhich may also store said first and second data.

The first and second data may be alterable from said manually operable means under the control of-a key operated switch or any other suitable form of secure re-programming facility, such as via the actual telephone line, as described above. The monitoring means may be arranged to remove time restrictions when the key operated switch is operated.

Telephone instruments in accordance with the invention will now be described by way of example only with reference to the accompanying drawings of which: Figure lisa block schematic diagram of a first telephone instrument in accordance with the invention; Figure2 is a block schematic diagram of a second telephone instrument having a differing barring arrangement; and Figure 3 is a block schematic diagram of a third telephone instrument in accordance with the invention.

Referring first to Figure 1 in which some of the more usual elements of a telephone instrument have been omitted for clarity, the circuit include a microprocessor 10 and a random access memory 11. A push-button keypad 12 is connected to the microprocessor 10 such that when keys of the keypad 12 are depressed data representing the respective key is transferred to the microprocessor.

When keys of the keypad 12 are used to indicate a telephone number to which a connection is required, the microprocessor 10 controls a decadic impulsing circuit 14 to provide impulses to a line 15, 15' to a telephone exchange (not shown).

As thus far described the telephone instrument behaves in the manner of conventional telephone instruments, that is when a user lifts the handset (not shown) of the instrument a switchhook 16 causes a resistive loop 17 to be applied to the line 15, 15'. The telephone exchange will return dial tone in the conventional manner and operation of keys of the keypad 12 causes the selected telephone number to be "dialled'! out of the line.

A further conventional facility provided by the telephone instrument is that known as repertory (or short code) dialling. Thus while depressing the key "P" and keying one of the keys 0-9 and further keys of the keypad 12 designating a telephone number up to ten telephone numbers may be stored under control of the microprocessor 10 in the Random Access Memory 11.

If a user of the instrument then wishes a connection to be established by use of one of the stored telephone numbers, operation of the key 'T' followed by the respective key 0-9 of the keypad 12 will cause the microprocessor 10 to fetch the appropriate telephone number from the Random Access Memory 11 for transmission to line by the impulsing circuit 14.

It is here noted that the function of the keys 'T' and 'P' is altered as hereinafter described when a key operated switch 18 is providing a signal to the microprocessor 10.

If the telephone instrument is connected to a private exchange which has connections accessible by way thereof to a public telephone network then the microprocessor 10 may be arranged on operation of the key 'T' to forward to the private exchange by way of the line 15, 15' the digit or digits of the code for selecting a connection to the public network. When dial tone is returned from the public telephone exchange the user may then operate one of the keys 0-9 to specify which of the numbers stored in the random access memory 11 is to be transmitted.

In order to simplify prohibition of groups of particular call types a group barring facility is provided by the microprocessor 10. In this method of operation holding down the key 'P' whilst the keyswitch 18 is operated and then depressing the key 'T' followed by one of the other keys of the keypad 13 indicating the barring group and then releasing the key 'P' permits only the calls indicated in the respective group shown in the following table:: Key Incoming PABX Repertory Local National International 1 '7 2 J J J J 3 J '7. \ J '7 4 J J J 5 J J J J J For example in operation once the keyswitch 1-8 is released having selected any barring group exgept group five anyattemptto key '010'-to the public telephone is identified by the microprocessor 10 as a prohibited number and the microprocessor causes a contact 19 which is in series with the switch hook 16 and the resistive loop 17 to operate. Operation of the contact 19 causes a discontinuity of the-loop across the line 15, 15' which ih turn causes the exchange to release.

It is here noted that if barring of group 4 is selected the microprocessor 10 will not permit reprogramming of the telephone numbers held in the random access memory 11 for that facility. The microprocessor 10 may also be arranged to prohibit reprogramming of the telephone numbers in the random access memory 11 SPECIFICATION Telephone instruments The present invention relates to telephone instruments and more particularly, but not exclusively to such instruments including repertory dialling facilities.

The monitoring means may be a micro-processor.

Preferably the monitoring means is a microprocessor which may also store said first and second data.

The first and second data may be alterable from said manually operable means under the control of a keyoperated switch or any other suitable form of secure re-programming facility, such as via the actual telephone line, as described above. The monitoring means may be arranged to remove time restrictions when the key operated switch is-operated.

Telephone instruments in accordance with the invention will now be described by way of example only with reference to the accompanying drawings of which: Figure 1 is a block schematic diagram of a first telephone instrument in accordance with the invention; Figure 2 is a block schematic diagram of a second telephone instrument having a differing barring arrangement; and Figure 3 is a block schematic diagram of a third telephone instrument in accordance with the invention.

When keys of the keypad 12 are used to indicate a telephone number to which a connection is required, the microprocessor 10 controls a decadic impulsing circuit 14to provide impulses to a line 15,15' to a telephone exchange (not shown).

As thus far described the telephone instrument behaves in the manner of conventional telephone instruments, that is when a user lifts the handset (not shown) of the instrument a switchhook 16 causes a resistive loop 17 be applied the line 15, 15'. The telephone exchange will return dial tone in the - conventional manner and operation of keys of the keypad 12 causes the selected telephone number to be "dialled" out of the line.

A further conventional facility provided by the telephone instrument is that known as repertory (or short code) dialling. Thus while depressing the key "P" and keying one of the keys 0-9 and further keys of the keypad 12 designating a telephone number up to ten telephone numbers may be stored under control of,the microprocessor 10 in the Random Access Memory 11.

In order to simplify prohibition of groups of particular call types a group barring facility is provided bathe microprocessor 10. In this method of operation holding down the key 'P' whilst the keyswitch 18 is operated and then depressing the key 'T' followed by one of the other keys of the keypad 13 indicating the barring group and then releasing the key 'P' permits only the calls indicated in the respective group shown in the following table:: Key Incoming PABX Repertory Local National International 1 '7 '7 2 J J J J 3 J J- J J J 4 J J J 5 J J J J '7 J For example in operation once the keyswitch-18 is released having selected any barring group except.

group five any attempt to key '010' to the public telephone is identified by the microprocessor 10 as a prohibited number and the microprocessor causes a contact 19 which is in series with the switch hook 16 and the resistive loop 17 to operate. Operation of the contact 19 causes a discontinuity of the loop across the line 15, 15' which in turn causes the exchange to release.

It is here noted that if barring of group 4 is selected the microprocessor 10 will not perniit reprogramming of the telephone numbers held in the random access memory 11 for that facility. The microprocessor 10 may also-be arranged to prohibit reprogramming of the telephone numbers in the random access memory 11 when barring groups 2 or 3 are selected. Alternatively the microprocessor 10 may be arranged to prohibit programming of barred numbers (e.g. international numbers for group 3, national or international numbers for group 2) unless the keyswitch 18 is first operated.

It will be appreciated that other selected barring facilities may be provided, for example a group may be allocated to permitting incoming calls only.

If the instrument is connected directly to a public telephone network then the group selection for 'PABX' outgoing calls only may be replaced by a category which permits only emergency (for example '999') calls.

A further facility provided by the instrument is that of limiting the duration of any call. For example if it is desired to restrict the duration of calls made from a telephone limited to the facilities provided by group 3 in the table above to say five minutes the method of programming is as follows: Operate the keyswitch 18 Hold down the key 'P' Press '3' to select group three Press '5' to select five minute timeout Release 'P' Release the keyswitch 18.

Any calls subsequently made from the telephone instrument will be monitored and timed by the microprocessor 10. If after, say, four and a half minutes the call is still in progress, the microprocessor 10 causes a warning tone to be applied to the earpiece (not shown) of the instrument.

If the handset has not been replaced at the end of the five minute period then the microprocessor 10 causes the contact 19 to release the connection as hereinbefore described.

It will be appreciated that the microprocessor 10 may be arranged such that the timeout is not applied to calls which only involve the private exchange. The microprocessor 10 is also arranged not to implement the timeout on emergency calls.

When the keyswitch 18 is operated then neither call barring nor call timeout is applied to calls made from the instrument.

Referring now to Figure 2 the instrument is basically a telephone which is similar in design to the Telephone No 746 of British Telecom. The telephone 19 is modified to include a microprocessor 21 and a bank of microswitches 101-110 which are controlled by a key operated lock (not shown).

The telephone includes a keypad 12 and a decadic dialling circuit 14 which may be an integrated circuit No AY5 - 9100 of General Instrument Corporation of America. A repertory store comprising two memories 26,27 which may each be an integrated circuit No AY5 - 9200 of General Instrument is also included.

To use the repertory store, programming of the microprocessor memory 26, 27 is effected by holding down the 'P' button of the keypad 12, followed by the location number within the particular memory bank, then the particular telephone number and, finally, releasing the 'P' button.

Retrieval of a number is effected by pressing the 'T' button of the keypad 12, followed by the location number.

Repetition of the last manually "dialled" number is achieved by pressing the 'T' button twice.

Each repertory dialled number can be up to any required number of digits usually eighteen maximum, as may the last number dialled. For PABX use, the access digit may be manually dialled prior to recalling a number from the repertory store.

Power for the memory may be provided from a primary battery 23 in case of external power source failure.

When connected to the telephone, the battery is maintained in a charged condition.

The barring switches 101-110 are provided inside the telephone housing to allow for any combination of barring options.

The barring switches are incorporated as part of the keyphone electronic assembly and a lock is provided on the telephone housing to prevent unauthorised access to these switches. Operation of the lock allows the housing to be removed or any barring conditions to be altered.

The barring switches 101-110, associated with the keyboard barring decoder 21, have the following respective call barring functions.

101. Incoming calls only.

102. 999 only.

103. Bar level 9.

104. Repertory from memory only.

105. Timer on.

106. PABX working.

107. Normal line.

108. Bar trunk calls.

109. Bar national calls.

110. Spare.

The timer on function switch 105 is associated with a clock generator 22 which may be an integrated circuit type AY5 - 9500 of General Instrument which is driven by the battery (BATT) 23 charged by a charger 24 and rectifier circuit 25.

The repertory function of the system comprises two AY5 - 9200 memories 16, 17 for storing selected telephone numbers 1-10 and 11-20.

Access to these two memories 16, 17 as well as the keyboard barring decoder 11, is provided by the key switch 18, to permit programming or reprogramming of the microprocessor with selected numbers, for repertory purposes, and predetermined barring functions, such as those listed above under 1-10.

The telephone unit 29 is a standard BT type 746, with microprocessors incorporated within its housing.

In use on detection of a barred code being dialled from the keypad 12 the barring decoder 21 causes an inhibit signal to be provided to the decoder dialler to prevent the digits of a telephone number being transmitted to line.

If the external power source is disconnected for a prescribed period of time, say, one minute, the system will automatically bar all outgoing calls, with the exception of prescribed numbers for emergency services and revert to incoming calls only.

Athird embodiment of the inventive call barring system will now also be described, again by way of example only, and with reference to Figure 3 of the accompanying drawings, wherein a block circuit diagram is illustrated.

This third embodiment of call barring system is very similar to the second embodiment described above with reference to Figure 2 and, for this reason, the equivalent components have been correspondingly numbered. However, in the system illustrated Figure 3, a microprocessor barring decoder 21 replaces the keyboard barring decoder 11, and associated barring switches, of Figure 2. Similarly, memories 1 and 2 (26', 27') of the circuit of Figure 3 have been used to replace the two memories 26,27 of the circuit of Figure 1, whilst any suitable form of clock generator 22', preferably included as part of the microprocessor unit 21, is used in Figure 3, as opposed to the specific clock generator 12 of Figure 2.

It will be appreciated that the memories 1 and 2 (26', 27') may be random-access memories as are the corresponding memories 16, 17 of Figure 1. However the functions of the memories 16,17 could be incorporated in a microprocessor. Furthermore, the microprocessor barring decoder 21' of the circuit of Figure 3 replaces the mechanical barring switches of the Figure 2, although the keyboard barring decoder 21 in Figure 2 could also be a microprocessor responsive to operation of the switches.

twill be appreciated that the call barring system in accordance with the invention can be included in any telephone unit to provide a respective call barring facility for, say, each telephone of a PABX system.

Additionally, the comparatively low manufacturing and installation costs of such a system are a distinct advantage over known, more cumbersome and less secure barring systems.

Claims

1. Atelephone instrument of the kind having manually operable means arranged to cause the transmission to line of signals defining digits of a telephone number, wherein means are arranged to store barring data in respect of each of a plurality of authorisation levels, which barring data determines for each of said authorisation levels which, if any, of a plurality of telephone numbers and/or codes are prohibited, means are arranged to permit preselection of an authorisation level from the plurality of authorisation levels and the instrument includes monitoring means responsive to said barring data and the preselected authorisation level of the instrument to monitor signals transmitted to line in respect of a telephone call to determine whether a telephone number and/or code so transmitted is a prohibited number and/or code and, if so, to prevent further progress of such a call.

2. Atelephone instrument as claimed in Claim 1, wherein said monitoring means is arranged to prevent further progress of such a call by preventing the transmission to line of a signal defining any subsequent digit of the prohibited telephone number and/or code.

3. Atelephone instrument as claimed in Claim 1 or Claim 2 in which said monitoring means is arranged to prevent further progress of such a call by causing disconnection of the line.

4. Atelephone instrument as claimed in Claim 1, Claim 2 or Claim 3 in which said barring data is alterable by use of the manually operable means of the keyboard and a key operable switch is provided so as to prevent unauthorised alteration of the data.

5. Atelephone instrument as claimed in Claim 4, in which said monitoring means is also responsive to said key operable switch to remove the prohibition in respect of any call made whilst the key operable switch is operated.

6. Atelephone instrument as claimed in any preceding claim including a repertory store which is programmable from the manually operable means with a plurality of telephone numbers

7. Atelephone instrument as claimed in Claim 6, in which said monitoring means is arranged to permit the transmission to line of digits defining a barred number and/or code which is stored in said repertory store.

8. A telephone instrument as claimed in Claim 6 or 7 in which reprogramming of said repertory store is inhibited unless the preselected authorisation level of the instrument is a prespecified authorisation level.

9. Atelephone instrument as claimed in Claim 6, when dependent on Claim 4 or Claim 5, in which reprogramming of said repertory store is inhibited unless said key-operable switch is operated.

10. Atelephone instrument as claimed in any preceding claim, in which said monitoring means is a microprocessor.

11. Atelephone instrument as claimed in any preceding claim in which the authorisation level of the instrument is programmable from said manually operable means.

12. A telephone instrument as claimed in any of Claims 1 to 10, in which the authorisation level of the instrument is preselected by use of a plurality of manually operable switches housed within the casing of the instrument.

13. Atelephone instrument as claimed in Claim 12, in which access to the manually operable switches is secured by a key operable locking mechanism.

14. Atelephone instrument as claimed in any preceding claim, including means arranged to disconnect the line if a permitted call is in progress for longer than a permitted time, so as to prevent continuation of such a call.

15. Atelephone instrument of the kind having manually operable means arranged to cause the transmission to line of signals defining digits of a telephone number wherein means are provided for storing first data defining a plurality of telephone numbers and/or codes and for storing second data in respect of each telephone number and/or code so stored and the instrument includes monitoring means responsive to said first data to determine from signals transmitted to line whether a call is a restricted call and, if so, is responsive to said second data to disconnect the line if such a call is in progress for longer than the permitted time so as to prevent continuation of such a call.

16. Atelephone instrument as claimed in Claim 15, in which the monitoring means is a microprocessor.

17. A telephone instrument as claimed in Claim 16, in which the first and second data are stored in said microprocessor.

18. A telephone instrument as claimed in Claim 15, Claim 16 or Cl aim 17, in which said first and second data are alterable by use of said manually operable means under control of a key operable switch.

19. Atelephone instrument as claimed in Claim 18, in which the monitoring means in inhibited when said key operable switch is operated so as to permit calls of any length.

20. Atelephone instrument including call barring facilities substantially as hereinbefore described with reference to Figure 1, Figure 2 or Figure 3 of the accompanying drawings.

21. Atelephone instrument including call time restriction facilities substantially as hereinbefore described with reference to Figure 1, Figure 2 or Figure 3 of the accompanying drawings.