System for locating display devices

A method for locating a display device in a system for displaying information in an area, the system comprising:

• a bus comprising a main bus and bus extensions;
• a central computer connected with the bus;
• a plurality of appenders located on the main bus, each appender having a unique address on the bus, each appender associated with a geographic portion of the area;
• a multiplicity of display devices, a plurality of which are connected with each bus extension, each display device having a unique address on the bus, each display device capable of detecting messages transmitted on the bus;
• each appender comprising means responsive to an occurrence of sending of a message by a display device on the bus extension associated therewith, for sending an append message subsequent to the conclusion of the message sent by the display device, the append message containing information indicative of the unique address of the appender;
• the method comprising the steps of:
• sending a message from the central computer containing the unique address of a particular display device;
• responding to the receipt of the message containing the unique address of a particular display device by sending a message from the particular display device;
• and
• sending a message from the appender associated with the bus extension on which the particular display device is located.

A method for use in a controller which is operatively connected with a bus transporting messages in a plurality of directions, said method comprising the steps of:

• detecting first ones of said messages on said bus in only one of said plurality of directions;
• detecting second ones of said messages on said bus in only said one of said plurality of directions;
• and
• transmitting a third message on said bus after detection of each of said first messages and each of said second messages, said third message containing an address identifying said controller on said bus.

A system for locating display devices comprising:

• a bus;
• a computer operatively connected with said bus;
• a plurality of appenders electrically connected with said bus, each of said appenders being identified by a different address on said bus and being associated with a geographic area;
• a plurality of display devices, each of said appenders electrically connected with one or more of said display devices in the geographical area associated with the appender, each of said display devices being identified by another different address on said bus;
• means in said computer for transmitting first messages on said bus,
• means in each of said display devices for receiving one of said first messages;
• means in each one of said display devices for transmitting second messages on said bus in response to a receipt of a said one of said first messages in the event of power outage of the one of said display devices, said second messages each containing information indicative of the power outage of the one of said display devices;
• means in each of said appenders for detecting, on said bus, ones of said second messages which are transmitted by ones of said display devices in the geographic area associated with the appenders;
• and
• means in each of said appenders for transmitting third messages after detection of said ones of said second messages, said third messages each containing information indicative of its address.

A system for locating display devices comprising:

• a bus;
• a computer operatively connected with said bus;
• a plurality of appenders electrically connected with said bus, each of said appenders being identified by a different address on said bus and being associated with a geographic area;
• a plurality of display devices, each of said appenders electrically connected with one or more of said-display devices in the geographical area associated with the appenders, each of said display devices being identified by another different address on said bus;
• means in said computer for transmitting first messages on said bus, said first messages containing information indicative of the address of one of said display devices;
• means in each of said display devices for receiving one of said first messages;
• means in each one of said display devices for transmitting second messages on said bus in response to a receipt of a said one of said first messages in the event of the contained information matching the address of the display device, said second messages each containing information indicative of the power outage of the one of said display devices;
• means in each of said appenders for detecting, on said bus, ones of said second messages which are transmitted by ones of said display devices in the geographic area associated with the appenders;
• and
• means in each of said appenders for transmitting third messages after detection of said ones of said second messages, said third messages each containing information indicative of its address.

A method for locating display devices in a system which comprises:

• a bus;
• a computer operatively connected with said bus;
• a plurality of appenders electrically connected with said bus, each of said appenders being identified by a different address on said bus and being associated with a geographic area;
• and a plurality of display devices, each of said appenders electrically connected with one or more of said display devices in the geographical area associated with the appenders, each of said display devices being identified by another different address on said bus;
• said method comprising the steps of:
• transmitting a first message on said bus from said computer;
• receiving said first message in each of said display devices;
• transmitting a second message on the bus by one of the display devices in the event of power outage of the one of said display devices, said second message containing information indicative of the power outage of the one of said display devices;
• detecting said second message on said bus by a particular appender associated with the geographic area where said one of said display devices is located;
• and
• transmitting a third message from said particular appender after detection of said second message, said third message containing information indicative of the address of said particular appender.

A method for locating display devices in a system which comprises:

• a bus;
• a computer operatively connected with said bus;
• a plurality of appenders electrically connected with said bus, each of said appenders being identified by a different address on said bus and being associated with a geographic area;
• and a plurality of display devices, each of said appenders electrically connected with one or more of said display devices in the geographical area associated with the appenders, each of said display devices being identified by another different address on said bus;
• said method comprising the steps of:
• transmitting a first message on said bus from said computer including first information indicative of an address of one of said display devices;
• receiving said first message in each of said display devices;
• transmitting a second message on the bus by one of the display devices in the event of the first information matching the address of the one of the display devices;
• detecting said second message on said bus by a particular appender associated with the geographic area where said one of said display devices is located;
• and
• transmitting a third message from said particular appender after detection of said second message, said third message containing information indicative of the address of said particular appender.