Communications: electrical – Condition responsive indicating system – With particular coupling link
Reexamination Certificate
1998-04-21
2001-09-11
Pope, Daryl (Department: 2736)
Communications: electrical
Condition responsive indicating system
With particular coupling link
C340S506000, C340S505000, C340S870030, C340S870030
Reexamination Certificate
active
06288639
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to wireless alarm systems having multiple alarm devices in communication with one or more control units, the control unit containing a system controller, receiver and transmitter; and in particular to such alarm systems where the control unit transmits messages to a wireless user interface device(such as a keypad and display), wireless remote siren and/or wireless remote dialer that indicate an alarm or change of status condition.
A recent innovation in security applications is the use of two-way wireless user interface devices, which are keypads or panic transmitters with system status indicators. These are portable devices, which may be used to control and interrogate the security system for system status. An example of such devices are the 5827BD and 5804BD products available from ADEMCO in Syosset, N.Y. These have the advantages of portability if required, or alternatively may be mounted at an installation, thus reducing the high costs of wiring a conventional wired user interface device. In addition, wireless remote sirens and dialers may be employed to reduce wiring and labor costs.
Typically during alarm system installation, a conventional central control unit is placed into an installation mode and its receiver sensitivity is reduced (see U.S. Pat. No. 4,754,261). This allows the installer to check the transmission signal margin of the alarm devices, i.e. window sensors, door sensors, etc. If the central control unit recognizes an alarm flag from the alarm device at reduced receiver sensitivity, then there will be adequate signal margin during normal operation. That is, if the radio environment changes during normal operation, due to movement of furniture etc., the alarm signals transmitted from the alarm devices have sufficient signal strength to be received by the central control unit receiver in this changed, adverse condition.
In the case where a wireless user interface device with signal receiver capabilities is being installed, ensuring an adequate signal margin between the central control unit transmitter and the wireless user interface device is typically more difficult because the wireless user interface devices currently may not be designed with a keypad selection or a switch to reduce their input sensitivity. It would be advantageous, when the central control unit receiver goes into installation mode (reduced sensitivity), at that same time to place the central control unit transmitter into reduced output power mode, thus obtaining an adequate signal margin in both the up link (user interface device to central control unit receiver) and down link (central control unit transmitter to user interface device).
It is also desirable to ensure that the wireless remote siren and dialer are installed with adequate signal margin so that if the radio environment changes during normal operation, the messages from the central control unit transmitter have sufficient signal strength to be received by the wireless remote device in this changed, adverse condition.
It is therefore an object of the present invention to provide a method for ensuring that an adequate signal margin exists between the central control unit and the wireless devices during an alarm system installation.
It is also an object of the present invention to provide an alarm system that provides means for transmitting between a central control unit and a wireless device at a reduced transmission level during installation mode and at a normal transmission level while not in installation mode.
It is yet a further object of the present invention to provide a common installation mode to verify communication between the central control unit and the wireless alarm devices (window sensors, door sensors, etc.) and at the same time verify communication between the central control unit and the wireless devices having receive capability (user interface devices, remote siren, and remote dialer).
SUMMARY OF THE INVENTION
In accordance with these and other objects, the present invention is a method for ensuring that an adequate signal margin exists between an alarm system's central control unit and its wireless devices. The wireless devices include a remote dialer, a remote siren, and optimally a user interface device such as a two-way(transmit and receive) portable keypad. This method typically is used during installation, which is initiated by manual input means at the central control unit and/or by selecting a user input code at the user interface device. The important feature of this method is that the central transmitter is put in a reduced power mode upon initiation of the installation mode.
During installation mode, the installer causes the central transmitter to transmit messages at low power and checks to see if the devices being installed take appropriate action. For example, while installing a user interface, the installer would request status from the central controller by entering user input codes into the user interface. The central transmitter would then transmit a status message at low power back to the user interface, which would display the status upon receipt. When the installer is locating wireless devices which do not display status, such as a remote siren, the installer would simulate an alarm condition by activating a manual input means, a sensor device or a user interface device such as a panic button. This causes an alarm received message to be transmitted at a reduced power level from the central transmitter to the wireless device being installed, which would take appropriate action upon receipt (i.e. activate siren).
When the wireless device does not indicate that it has successfully received the reduced power message, then the wireless device is relocated by the installer and a reduced power message is retransmitted to the wireless device. The installer continues this process until the wireless device indicates that it has successfully received a reduced power message. A reduced power level of approximately 12 dB ensures that the wireless device is installed with adequate signal margin for normal operation.
In addition, reduced central transmitter output power may be coincident with reduced central receiver sensitivity. The installer can conveniently ensure system signal margin in both up and down links by triggering or simulating an alarm condition at an alarm device (i.e. opening a window) and checking that the wireless devices indicate an alarm condition.
Finally when the installation is completed, the installer goes into normal operation mode by initiating manual input means at the central control unit or by selecting a user input code for normal operation at a wired or wireless user interface device. There is also a safety feature that ensures the alarm system will not be left in install mode by the installer. An install timer, which is set upon entering the install mode, causes the alarm system to go back into normal mode after a predetermined amount of time.
The present invention is embodied by an alarm system comprising a central control unit with a transmitter and a plurality of wireless devices with means for receiving messages from the central transmitter. The central control unit operates in both a normal mode and an install mode. The central transmitter provides means for transmitting at two different output power levels, the output being transmitted at a higher power level during normal operation, and the output being transmitted at the lower power level during an installation mode. The central transmitter broadcasts, electromagnetically such as by radio frequency (RF) or infrared (IR) means, alarm received messages and other status and control messages to the wireless devices. The wireless devices comprise receiving means for receiving messages from the central transmitter and indication means for indicating when the message has been successfully received. The indicating means may be an audible sound from a remote siren, activation of a remote dialer, and/or a visual display or audible sound from a user interface de
Barkume Anthony R.
Greenberg & Traurig
Pittway Corporation
Pope Daryl
LandOfFree
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