GB2241599A

GB2241599A - Intruder alarm with remote reset

Info

Publication number: GB2241599A
Application number: GB9004522A
Authority: GB
Inventors: David Huddart
Original assignee: TUNSTALL SECURITY Ltd
Current assignee: TUNSTALL SECURITY Ltd
Priority date: 1990-02-28
Filing date: 1990-02-28
Publication date: 1991-09-04
Anticipated expiration: 2010-02-28
Also published as: GB2241599B; GB9004522D0

Abstract

A controller e.g. an intruder alarm controller, comprises a pseudo-random counter which can be activated to display its current count and to compute but not display the next count in its sequence, the controller being arranged to adopt a predetermined condition if then the user enters a code corresponding to the newly computed count. In order to reset an intruder alarm for example, the user telephones a supervisor at a central station to report the displayed count: the supervisor can then provide the next count in the sequence from a look-up table.

Description

Intruder Alarm with Remote Reset This invention relates to an intruder alarm, and more particularly to an intruder alarm capable of being reset from a remote location.

Intruder alarms, particularly those having remote signalling, are often required to have a reset facility not normally available to the user. This is because the response authorities (usually the police) require the intruder alarm installation to be checked after an alarm, before being brought back into service (or reset). Historically, it was necessary for an engineer to visit the premises at which the alarm was installed, and carry out a full injection. Upon completing his inspection, the engineer would reset the alarm using the secure facility, e.g. a switch internal to the control panel, or an engineer code entered cn the keypad of the control panel.

Nowadays it is no longer always necessary for an engineer to visit the protected premises in order to carry cut an inspection, but there is still a requirement for the alarm to have a reset facility not normallly available to the user.

Thus, alarms can be reset over the public subscriber telephone network, using the same communications equipment as is used for sending alarm signals to a central station Once the supervisory personnel at the central station are satisfied that an engineer's visit is unnecessary, a command can be communicated from the central station to the alarm in order to reset the latter. However, there is no clear standard for this facility and few central or supervisory stations are suitably equipped. The personnel at the central station could instruct the user by telephone to reset the alarm by entering the engineer's code on the control panel keypad: however once used, the user would be able to use the same code to reset the alarm on future occasions, and so the requirement for a reset facility not normally available to the user, would not be complied with.

We have now devised an arrangement by which a reset instruction can be given to the user over the telephone from a central station, whilst maintaining the requirement for this reset facility to be not normally available to the user.

In accordance with this invention, there is provided a controller having a pseudo random counter which can be activated to display its current count and to compute but not display the next count in its sequence, the controller being arranged to adopt a predetermined condition if then the user enters a code corresponding to the newly computed count of the counter.

Thus in order to reset the controller (which may be an intruder alarm controller or control panel), the user can activate the counter to display its current count. The user can inform the supervisor at the central station of this current count over the telephone. The supervisor can then refer to a look-up table and inform the user over the telephone of the net count in the sequence of the counter. The user enters this code, which should agree with the count newly computed by the counter in order to effect reset automatIcally. The next time that the controller requires resetting, the next code in the counter 5 sequence will be required and has to be obtained from the central station in the same manner.

Preferably the reset facility is accessed by the user entering his user code on the controller keypad and then operating an appropriate key or keys according to a menu system of the controller, whereupon the pseudo random counter is activated to display its current count and compute but not display the next count in its sequence.

The pseudo random counter provides a predetermined sequence of counts or codes and progresses through the sequence each time it is activated. Preferably the counter is implemented in software on the controller microprocessor. It may have a code length of e.g. 255 (27-1). Its feedback code may be controlled by part of the engineer's code for the equipment, e.g. the two least significant digits of the engineer's code. The feedback code controls the sequence but not the number of counts within the sequence. The look-up table held at the central station preferably comprises a printed copy of all count sequences (255 in length) for each feedback code (up to 100 but perhaps limited to 20).

Similar arrangements may be provided for verification in respect of equipment other than intruder alarms.

Thus the equipment may include a controller with display, keypad and pseudo random counter, as in the intruder alarm controller just described. The user may be required to enter a PIN code to activate the counter, then report the displayed count over the telephone to a supervisor, who can refer to the look-up table to find the next count in the sequence and report this to the user.

When the user keys in this new code, the controller is able to accept the user and adopt a set condition.

Claims

1) A controller having a pseudo-random counter which can be activated to display its current count and to compute but not display the next count in its sequence, the controller being arranged to adopt a predetermined condition if then the user enters a code corresponding to the newly computed count of the counter.

2) A controller as claimed in claim 1, comprising a keypad requiring entry of a predetermined code by the user to activate said counter.

3. An intruder alarm controller as claimed in claim 1 and substantially as herein described.

3) An intruder alarm controller comprising a controller as claimed in claim 1 or 2, arranged to adopt a reset condition when the user enters a code corresponding to the newly computed count of the counter.

Amendments to the claims have been filed as follows 1. An intruder alarm controller having a pseudorandom counter which can be activated to display its current count and to compute but not display the next count in its sequence, the controller being arranged to adopt a reset condition if then the user enters a code corresponding to the newly computed count of the counter.

2. A controller as claimed in claim 1, comprising a keypad requiring entry of a predetermined code by the user to activate said counter.