GB2324224A

GB2324224A - Method of call screening

Info

Publication number: GB2324224A
Application number: GB9806191A
Authority: GB
Inventors: Wynn Quon
Original assignee: Mitel Corp
Current assignee: Microsemi Semiconductor ULC
Priority date: 1997-04-07
Filing date: 1998-03-23
Publication date: 1998-10-14
Anticipated expiration: 2018-03-23
Also published as: GB2324224B; GB9806191D0; CA2232168A1

Abstract

A method of call screening comprising receiving a call to a subscriber directory number, determining a calling directory number of the call, checking a first list of calling directory numbers to be affected by a screen and a second list of times during which said directory numbers are to be blocked or permitted through the screen to determine whether a call incoming from the calling directory number should be blocked at a real time contained within the times, and completing the call to a line associated with the subscriber directory number in the event the call is not to be blocked at the real time of the call.

Description

METHOD OF CALL SCREENING This invention relates to the field of telephony, and in particular to a method of call screening BACKGROUND TO THE INVENTION Telephone subscribers are often inconvenienced by commercial or business calls at inappropriate times, or by prank callers which call during nighttime hours.

Some central offices have a feature which attempts to avoid the inconvenience, which allows a telephone subscriber to receive calls only from a predefined list of telephone directory numbers, and to block all others.

However it has been found that this feature is seldom used due its inflexibility. For example, calls can be received from all of the directory numbers on the list, and all others are blocked, 24 hours per day, or until disabled. If call blocking is to be done each evening and disabled each morning, this must be done each day by the subscriber, i.e. attendance must be made to the feature twice per day. This is very inconvenient for busy subscribers.

SUMMARY OF THE INVENTION In accordance with the present invention, subscribers can establish a screen of calling directory numbers, and link the directory numbers which are=on the list to time intervals. Thus, for example, inane embodiment, calls from different numbers on the list can be allowed to be completed during time intervals linked to specific time intervals, and all others blocked. In another embodiment, incoming calls from all directory numbers not on the list can be blocked during one or plural time intervals, and calls from directory numbers on the list can be allowed to be completed. In accordance with another embodiment, separately or in conjunction with the above embodiments, all calls can be allowed to be completed except for certain listed directory numbers during intervals linked to the listed directory numbers.

In accordance with an embodiment of the invention, a method of call screening comprises receiving a call to a subscriber directory number, determining a calling directory number of the call, checking a first list of calling directory numbers to be affected by a screen and a second list of times during which the directory numbers are to be blocked or permitted through the screen to determine whether a call incoming from the calling directory number should be blocked at a real time contained within the times, and completing the call to a line associated with the subscriber directory number in the event the call is not to be blocked at the real time of the call.

BRIEF INTRODUCTION TO THE DRAWINGS A better understanding of the invention will be obtained by considering the detailed description below, with reference to the following drawings, in which: Figure 1 is a block diagram of a system on which the present invention can be carried out, Figure 2 is a flow chart of steps of the present invention, Figure 3 is a diagram of contents of a memory in accordance with an embodiment of the invention, Figure 4 is a flow chart of steps of the present invention, Figure 5A is a diagram illustrating a time line of blocked and unblocked periods, to aid understanding another embodiment of the invention, and Figure 5B is a diagram of contents of a memory in accordance with an embodiment of the invention relating to the timeline of Figure 5A.

DETAILED DESCRIPTION OF EMBODIMENTS OF THE INVENTION Figure 1 illustrates a block diagram of a telephone switching system which can carry out the invention, which is based on a telephone system described in U.S. patent 4,615,028 issued September 30, 1986, invented by Conrad Lewis and Gino Totti, and in U.S. patent 4,616,360 issued October 7, 1986, invented by Conrad Lewis. In that system, a central control 1, operating under control of programs stored in memory 3, communicates with memory 3 and with at least one circuit switch 5 and with at least one message switch 7 via bus 9. The control 1 controls cirduit switch 5 to connect calls between peripherals such as telephone sets 11 and trunk circuits 13, and extends the peripherals' lines connected to the peripheral switch 15 to circuit switch 5 for interconnection by sending control messages to the peripheral switches via the message switch 7. A processor 17 controls peripheral switch 15, and is controlled by messages received via peripheral switch 15 from processor 1.

To implement the present invention, an auxiliary memory or portion of an existing memory such as memory 3 stores a database such as will be described below. The database 19 can be connected to bus 9 for access by the processor 1, or can be connected for access by processor 17. The embodiment below will be described with database 19 connected to bus 9, but a person skilled in the art having read the aforenoted patents will recognize how the database can be accessed and used in conjunction with processor 17 instead.

With reference to Figure 2, in accordance with an aspect of the invention, a subscriber lifts the handset of a telephone 11 (or does the equivalent by pushing a button on a feature phone or virtual button displayed on a computer associated with a telephone in a computer-telephone integration system (CTI), i.e. goes offhook. Under control of processor 17, the peripheral system connects a dual tone multifrequency (dtmf) receiver to the offhook subscriber line via the peripheral switch 15.

The subscriber dials a feature access code, which is translated to a message by dtmf receiver 19 and processor 17, and is sent via the message system to processor 1. Under control of programs stored in memory 3, processor 1 then causes an automatic dialog to ensue with the subscriber, by sending messages to processor 17 to cause a digital signal processor (dsp) 21 to be connected to the offhook subscriber line and voice synthesize prompt questions which are responded to by the user keying dtmf digits. Alternatively, a voice response unit is connected to the offhook subscriber line to prompt questions and recognize the meaning of spoken responses.

The prompt questions request the subscriber to key in the directory number of a prospective caller which is to be screened, and then to key numbers corresponding to times which the calling directory number is to be allowed to complete calls to the offhook line. By keying. e.g a &num; sign, the completion of a sequence can be indicated.

Alternatively, instead of voiced prompt! and responses, if a CTI computer or other display is used in conjunction with the offhook telephone, the prompts and responses can be made by dialog box and keyboard.

In an embodiment of the invention, the directory numbers are stored in a permissions list in database 19, in a form such as is shown in Figure 3. This list is comprised of an identity of the subscriber which has invoked the feature, e.g. such as the subscriber directory number, a list of prospective calling subscriber directory numbers which are to be allowed to complete calls to the subscriber with the exclusion of all other calls from directory numbers which are not on the permission list during "blocked intervals", and a list of blocked time intervals during which all calls other than those from directory numbers on the permission list are to be excluded.

Following entry of the permissions list and block times, the subscriber hangs up (goes on hook).

With reference to Figure 4, when a call is received to be completed to the subscriber line, the calling party's directory number is identified by the system using automatic number identification (ANI), and the identified directory number is checked against the permissions list in the called party's database record, e.g. as shown in Figure 3, by the processor 1 accessing database 19. If the identified directory number is on the permissions list, the call processor 1 controls completion of the call to the subscriber line, e.g. by ringing that line.

If the identified directory number is not on the permissions list, the blocked intervals portion of the database record is read under control of processor 1, and the blockout times are checked against a real time clock contained in the switching system. If the real time is outside the blocked intervals, the processor controls completion of the call.

If the real time is inside one of the blocked intervals, the call is not completed. It is preferred that instead of merely returning continuous ringing tone to the calling party to indicate non-completion of the call, a voice unit should be connected to the line or trunk on which the incoming call is carried, e.g. under control of processor 17 via peripheral switch 15. The voice unit can announce that incoming calls to the called subscriber are currently blocked. The voice unit can also announce, if desired in implementation of the service, the time periods in which the called lines would be unblocked.

It should be noted that in this and other embodiments, the directory numbers identify the subscribers, and may be distinguished from identification of the subscriber lines, since different subscribers can have different directory numbers associated with a single subscriber line. In the latter case, for example, a subscriber having an identity of one directory number can have a permission list relating to the line, and another subscriber having an identity of another directory number can have a permission list relating to the same line. The two permission lists need not correspond as to time, and can operate independently of each other. Thus for example a permitted incoming call for a first subscriber which is not on the list of the other subscriber can ring the line to reach the first subscriber even though it would be otherwise blocked for the reason of not being included on the permissions list of the other subscriber.

Figure SA is a timeline of a day, illustrating another embodiment of the invention. As the example shown, it is desired to block all calls exceptciirectory numbers A, B and C during an interval 6:00 AM to 9:00 AM, and to further unblock calls in addition from directory number D during the interval 8:00 AM to 9:00 AM.

In addition, it is desired to block only calls from directory number D during the interval form 6:00 PM to 7:00 PM.

During other periods, no calls are blocked.

Reference is now made to Figure 5B which illustrates contents of the database for the subscriber.

A first sublist 30 is a permissions list which contains the directory numbers of calls which are to be blocked during particular time intervals. In other words, sublist 30 can be characterized as meaning "block all calls except those incoming from the directory numbers listed in the sublist, during linked time intervals".

A second sublist 31 contains directory numbers of incoming calls which are to be blocked during particular time intervals. In other words, sublist 31 can be characterized as meaning "block no calls except those incoming from directory numbers listed in sublist 31, during linked time intervals".

Sublist 32 contains linked time intervals for sublist 30, and sublist 33 contains linked time intervals for sublist 31.

Each directory number in sublists 30 and 31 contain a pointer which links it to a respective sublist 32 or 33. Thus for example, the record of directory number A has a pointer to a sublist 32 which contains the time interval 6:00 AM - 9:00 AM (and can contain other additional time intervals), the record of directory number,B has a pointer to a sublist 32 which contains the time interval 6:00 AM - 9:00 AM, and=the record of directory number C has a pointer to a- sublist 32 which contains the time interval 6:00 AM - 9:00 AM.

The record of directory number D in sublist 30 has a pointer to a sublist 32 which contains the time interval 8:00 AM - 9:00 AM.

The sublist 31 contains a record of directory number D and a pointer to a sublist 33, which contains the time interval 6:00 PM - 7:30 PM.

The processor 1, in processing the data carried in the sublists should ignore exclusions that result from time overlaps. Thus, in considering sublists 30 33, if a call to the subscriber from any directory number arrives prior to 6:00 AM, it is completed. From 6:00 AM to 8:00 AM, all incoming calls from directory numbers other than A, B and C are blocked, and from 8:00 AM to 9:00 all incoming calls from directory numbers other than A, B, C and D are blocked.

From 9:00 AM to 6:00 AM the next day, no calls are blocked, except for calls from directory number D, which is blocked between 6:00 PM and 7:30 PM, since that directory number is contained in sublist 31 (meaning, "block no calls except block calls from directory number D between 6:00 PM and 7:30 PM).

Once the screening schedule is setup, it is repeated daily, which results in the subscriber not having to enable and disable screening on an as needed or on an as not desired basis, substantially reducing attention and inconvenience to the user.

Further, the system can include different lists and/or sublists for designated days, such as weekends and holidays. Particularly if the content of the lists and sublists are established on a display, e.g. by displaying a time and date diary, the lists, sublists and their content can be established to control the screening far into the future, to include holidayswhich do not conform to weekends, to conform to needs of temporary expected visitors, etc.

The content of the sublists can be entered by voiced or displayed prompts, as described earlier.

A person understanding this invention may now conceive of alternative structures and embodiments or variations of the above. All those which fall within the scope of the claims appended hereto are considered to be part of the present invention.

Claims

1. A method of call screening comprising receiving a call to a subscriber directory number, determining a calling directory number of the call, checking a first list of calling directory numbers to be affected by a screen and a second list of times during which said directory numbers are to be blocked or permitted through the screen to determine whether a call incoming from the calling directory number should be blocked at a real time contained within said times, and completing the call to a line associated with the subscriber directory number in the event the call is not to be blocked at the real time of the call.

2. A method as defined in claim 1 in which the first list is comprised of calling directory numbers which are permitted through the screen, and the second list is comprised of intervals during which all calls are blocked except those directory numbers which are on the first list.

3. A method as defined in claim 1 in which the first list is comprised of first and second sublists, and in which the second list is comprised of third and fourth sublists, a first sublist being comprised of calling directory numbers which are not to be blocked during intervals listed on corresponding third sublists, a second sublist being comprised of calling directory numbers which are to be blocked during intervals listed on corresponding fourth sublists, and further including the steps of blocking all calls listed on the first sublists during linked intervals listed on the third sublists, except for calls listed on the second sublist during linked intervals listed on the fourth sublist, and otherwise completing incoming calls to a line associated with the called subscriber directory number.

4. A method as defined in claim 2 including applying an announcement to lines carrying incoming calls which are blocked, advising that incoming calls to the called subscriber are currently blocked.

5. A method as defined in claim 4 including applying a further announcement advising of a time or time periods when the called line would be unblocked.

6. A method as defined in claim 3 including applying an announcement to lines carrying incoming calls which are blocked, advising that incoming calls to the called subscriber are currently blocked.

7. A method as defined in claim 6 including applying a further announcement advising of a time or time periods when the called line would be unblocked for a corresponding calling directory number.

8. A method as defined in claim 1 further including the steps of storing, in association with a subscriber directory number, said first list of prospective calling directory numbers to be affected by a screen, and storing a second list of times during which said directory numbers are to be blocked or permitted through the screen, in association with said prospective calling directory numbers.