Alert Message Communication System

The present invention relates to communication systems and particularly to such systems capable of providing a subscriber originated alert message to other subscribers in the system which have been selected by the message originater.

Communication systems, and particularly two-way communication systems are well known in the art. In addition, communication systems capable of providing an alert message to selected subscribers are also known in the art. However, such prior art systems do not readily enable a subscriber to provide an alert message to a variable list or directory of subscribers or recipients for this message which may readily be varied at the will of the originating subscriber. Nor do they provide for priority queueing of multiple alert messages which may be received by a different subscriber and which may be selected by that subscriber in any order desired. These features are important to a two-way dynamic communication system in which the subscriber recipients may be rapidly changing as conditions vary, such as in a shipping market, commodities market, security market or money market environment, such as in an international system in which selected subscribers at different geographic locations, such as for example Paris, Frankfurt, Zurich, London, Hong Kong and New York may be substantially instantaneously provided with a common alert message. Thus, there are no satisfactory prior art alert communication systems known to applicants which have sufficient flexibility to disseminate and receive fast-moving market information on a world-wide basis, in particular where the desired recipients and contributors constantly change. These disadvantages of the prior art are overcome by the present invention.

The present invention relates to communication systems capable of providing a subscriber originated alert message to other subscribers in the system or network which have been selected by the message originator. Both the content of the alert message and the designated recipients may be readily varied at will by the subscriber at his keystation which comprises a keyboard for requesting and inputting textual data messages and associated data control signals and a display, such as a video display, for providing a textual display of the keyboard generated data. The network, which is a telephone type distribution network, includes a plurality of message routing node interfaces at different geographic locations to which are connected a plurality of keystation controller interfaces which interface the various keystations to the network. Each keystation controller has associated display control logic and local storage for locally storing and displaying alert messages which have been directed to the keystations associated with that keystation controller as well as for storing other retrievable data which the keystation may select for display. Each keystation is assigned a locally storable control page which contains the identification of keystation recipient groups throughout the network which a given subscriber keystation has predefined for receipt of his alert message. The control page, which may be varied at will by the subscriber, contains different sets of message routing logic control signals which correspond to different selected address groups of designated subscriber recipients. The control page is locally stored in the node interface logic for routing the alert message originated by an associated subscriber to the appropriate keystation controller interfaces logic for subsequent local storage and display selection by the designated subscriber recipients. Each keystation controller interface has a unique associated address code so that it may be uniquely identified in the message routing logic control signal. A printer is associated with each keystation controller interface for providing a hard copy print out of the referred alert messages if desired. Once a control page has been predefined, the originating subscriber may rapidly select different sets of subscriber keystations recipient groups for a given alert message. The subscriber keystation may contribute remotely storable retrievable data to the network as well as alert messages, and message routing data and selection control signals, so that the data message may rapidly inform selected subscribers of an event, such as market availability, while referring those subscribers to other retrievable data if they have an interest. This is particularly useful in rapid market dealing, such as in the shipping or commodities market.

FIG. 1 is an overall system functional block diagram illustrating a typical alert communications network;

FIG. 2 is a functional block diagram illustrating a typical node in the network of FIG. 1 of the type having associated local concentrator computers;

FIG. 3 is a functional block diagram, similar to FIG. 2, illustrating a typical node in the network of FIG. 1 of the type having no associated concentrator computers;

FIGS. 4A-4B are illustrative of the operation of the watchdog timer portion of the nodes of FIGS. 2 and 3, with FIG. 4A being a functional block diagram of the interface between the watchdog timer, line switch and dual processors and with FIG. 4B being a graphic illustration of the watchdog timer timing cycle;

FIGS. 5A-5B are illustrative of the universal line switch portion of FIGS. 2 and 3, with FIG. 5A being a functional block diagram of a typical line switch daisy-chain, and with FIG. 5B being a schematic, partially in block, of a typical switch network module for the universal line switch of FIG. 4A;

FIGS. 6A-6B are an overall system functional block diagram of a typical terminal controller, with FIG. 6A generally functionally illustrating the overall controller configuration, omitting certain portions for clarity, and with FIG. 6B further functionally illustrating the terminal controller;

FIGS. 7A-7K are schematic diagrams of the typical preferred terminal controller of FIGS. 6A-6B, with FIGS. 7A-7F comprising a schematic diagram of the CPU control portion of the controller, FIG. 7G comprising a schematic diagram of the connector assembly portion of the controller and with FIGS. 7H-7K comprising a schematic diagram of the display generator and memory portion of the controller; and

FIGS. 8A-8E are illustrative examples of typical page displays in connection with provision of an exemplary alert communication message for shipping market data, with FIGS. 8A-8C relating to a typical control page, FIG. 8D relating to a typical ALERTS PAGE, and FIG. 8E relating to a typical page of text.

Referring now to the drawings in detail, and initially to FIG. 1 thereof, an overall system block diagram illustrating a typical communications network, generally referred to by the reference numeral 20 is shown. For the purposes of illustration, the network 20 shall be described in terms of a communications network having nine nodes 22, 24, 26, 28, 30, 32, 34, 36 and 38 by way of example. Furthermore, for the purposes of illustration, the communications network 20 is assumed to be a worldwide distribution network and, as such, the various nodes are shown by way of example as being located in Frankfurt, Zurich, London, New York and Hong Kong with a remote connection of one of the nodes, node 28, located in Zurich to Paris. A typical node, such as node 30 located in London, will be described in greater detail hereinafter with reference to FIG. 2. As will also be described in greater detail hereinafter, each of the nodes 22 through 38, respectively, functions substantially autonomously. The various nodes 22 through 38 are, in reality, computer configurations as illustrated in FIG. 2. As will be further described in greater detail with reference to FIG. 2, preferably, local concentrator computers are associated with the nodes. In the example of FIG. 1, however, only certain of the nodes, namely nodes 22, 26, 28, 30 and 32, by way of example, have associated local concentrator computers with the primary function of the local concentrator computer being to expand the number of lines which could be serviced by a given data base or node. Of course, if desired, nodes 24, 34, 36 and 38 could also employ local concentrator computers if it were desired to similarly expand the number of lines servicable by these nodes. By way of example, node 22 has four associated local concentrator computers 40, 42, 44 and 46 with, as will be described in greater detail hereinafter, concentrators 40, 42 and 44 being active and concentrator 46 being a stand-by concentrator in the event that one of the active concentrators 40, 42 or 44 fails so that its function can be assumed without any loss by the spare concentrator 46. Similarly, node 26 has three associated local concentrator computers 48, 50 and 52 with concentrators 48 and 50 being active and with concentrator 52 being a spare; node 30 also has four associated local concentrator computers 54, 56, 58 and 60 with concentrators 54, 56 and 58 being active and concentrator 60 being a spare; and node 32 has three associated concentrator computers, by way of example, 62, 64 and 66 with concentrators 62 and 64 being active and with concentrator 66 being a spare. As was previously mentioned, with respect to node 28, it has two pair of local concentrator computers 68-70 and 72-74 which are remotely located in another city, such as Paris. Each of these pairs 68-70 and 72-74 consists of an active concentrator computer 68, 72 and a stand-by concentrator computer 70-74 with these concentrator pairs 68-70, 72-74 preferably being connected via telephone land lines to the node 28 located in Zurich. Each local concentrator computer 40 through 74 is, respectively, a processor which handles network communication functions and supports terminal controllers associated therewith, to be described in greater detail hereinafter with reference to FIG. 2, which terminal controllers 80, by way of example in FIG. 2, provide an interface between the subscriber terminal, 82 by way of example in FIG. 2, and the respective node, such as node 30. The nodes, such as node 30, comprise a host computer pair with the host computer being the main communications interface between other nodes in the system and the various associated local concentrators and the data base. As also shown and preferred in FIG. 1, node 30 receives external data, such as news from an external computer system 90 as is also illustrated for node 32 which receives external data such as news from a different external computer system 92. In addition, as further illustrated in FIG. 1 another computer 34 may be used as a two-way data interchange for providing additional data to data base 92 and to node 36 as well as for providing the data from node 36 to an external system, such as a cable television system if desired. The various nodes 22 through 38 are connected to adjacent nodes via trunk lines, such as at 4800 baud, which can either be conventional telephone land lines or satellite communications. As will be described in greater detail hereinafter, these various trunk lines are used to distribute subscriber originated data, such as alert communication messages, from the point of origin at the individual subscriber or keystation 82 to the various points of reception at other subscriber designated keystations throughout the world-wide network 20.

Referring now to FIG. 2, a typical node, such as node 30 located in London in the example of FIG. 1, is shown. FIG. 2 also illustrates the various concentrator computers 54, 56, 58 and 60 located at node 30 along with the associated communications equipment necessary for supporting the host computers 30A and 30B. For purposes of illustration, host computer 30A is assumed as being the active computer in the example of FIG. 2 and host computer 30B is assumed as being the stand-by computer. The two host computers 30A and 30B are shown as being interconnected by trunk lines 100 and 102 and have their respective states controlled by a watchdog timer network 104 to be described in greater detail hereinafter. In addition, there is a universal line switch 106, also to be described in greater detail hereinafter, which handles the switching interface with the other various nodes in the network 20. Each host computer, such as computer 30A, preferably consists of the processor itself, and associated supporting peripherals. Thus, for example, computer 30A may be a conventional PDP11/34 manufactured by Digital Equipment Corporation and associated peripherals such as the following Digital Equipment Corporation peripherals, namely: a DL11-W line frequency clock and serial interface, an RJS04 fixed head disc, an RK11 dual drive moving head disc system, an RX11 dual drive floppy disc, a DH11 16 line asynchronous multiplexer, a DMC11-AL 56 kilobits per second synchronous interface for each of the local concentrator computers associated with the host computer, such as the four concentrators 54, 56, 58 and 60 associated with either host computer 30A or 30B, and a DL11-W interface for communication with the watchdog timer 104. In the example of node 28 having remotely located concentrator computers 68, 70, 72 and 74, a DMC11-AR 9.6 kilobits per second synchronous interface is preferably used in place of the DMC11-AL interface. In addition, in the example of node 28 having the remotely located concentrator computer 68, 70, 72 and 74, node 28 can also support additional subscribers through additional DH11 interfaces.

By way of example, a typical local concentrator computer, such as concentrator 54, preferably contains a conventional processor and associated peripherals, such as a Digital Equipment Corporation PDP11/34, a DL11-W serial interface, a KW11-P programmable clock, an RX11 dual drive floppy disc system, six 16 line asynchronous DH11 multiplexers for communication with six subscriber terminal controllers 80 and two DMC11-AL 56 kilobits per second synchronous interfaces for communication with either of the host computers 30A or 30B. In the example of the remotely located concentrator computer 68, 70, 72 and 74, in place of the two aforementioned DMC11-AL synchronous interfaces, four DMC11-AR synchronous interfaces are employed with one being associated with each of the four concentrator computers 68, 70, 72 and 74. In addition, the 96 line outputs of each of the local concentrator computers 54, 56, 58 and 60 are provided to a conventional line switch 108 which conventionally switches the signals on the various 96 line inputs 110, 112, 114 to the respective lines 116, 118 and 120. In the instance of a failure of one of the active concentrators 54, 56 or 58, then the 96 input lines associated with that particular concentrator are switched so as to be associated with the 96 output lines 122 associated with the spare concentrator computer 60 which then takes over the function of the failed concentrator computer. Since the connections between the various subscriber keystation terminal controllers 80 and the nodes, such as node 30, are provided via telephone lines, with one such line 122 being shown by way of example in FIG. 2, operating at, for example, 1200 baud or bits per second, conventional modems 124 and 126, respectively, are provided at each end of the associated telephone line 122. The modem 126 at the subscriber's office preferably is connected to a terminal controller 80 to be described in greater detail hereinafter with reference to FIGS. 6A-6B and FIGS. 7A-7K, which controller 80 acts as communications oriented intelligent terminal employing a microprocesser for controlling, by way of example, up to four subscriber keystations 82 and also locally storing an alert message page, which page is preferably unique to the keystations 82 associated with the particular controller 80. In addition, the controller 80, as will be described in greater detail hereinafter, can request and retrieve information from the central system or node 30 such as news data for display on the various video display screens associated with the keystations being serviced by the controller 80.

Referring again to FIG. 1, three such terminal controllers 80A, 80B and 80C are illustrated, by way of example, associated, respectively, with concentrator 54 at node 30, concentrator 40 at node 22 and directly with the host computer at node 34. The absence of the concentrator in connection with node 34 does not in any way affect the functioning of the system but merely limits the number of lines which can be serviced by node 34. In addition, each of the controllers 80A, 80B and 80C has an associated local printer 150A, 150B and 150C, respectively for local printing of news data or alert messages as will be described in greater detail hereinafter. In addition, terminal controller 80A is connected to concentrator 54 via modems 126A and 126B and telephone line 122, terminal controller 80B is connected to concentrator 40 via modems 152A and 152B and telephone line 154, and terminal controller 80C is connected to node 34 via modems 156A and 156B and telephone line 158. The various exemplary keystations illustrated in FIG. 1 are respectively labelled 82 and 160 for terminal controller 80A, 162 and 164 for terminal controller 80B and 166 and 168 for terminal controller 80C. As shown and preferred in FIG. 2, the respective terminal controller 80 is connected to the associated modem 126 via conventional 4 wire EIA line 170.

Referring now to FIG. 3, a typical node configuration for node 34 by way of example, wherein concentrator computers are not associated with the host computers is shown. Thus, as can readily be seen by comparing FIGS. 2 and 3, the primary difference between the node configuration 34 illustrated in FIG. 3 and the node configuration 30 illustrated in FIG. 2 is the absence of the concentrators 54 through 60 and the subsequent replacement of the concentrator line switch 108 by the universal line switch 106A which is preferably functionally identical to universal line switch 106 in FIG. 2 with the exception that it is capable of switching 96 lines as opposed to the 16 lines switched by the universal line switch 106 in FIG. 2. Thus, a watchdog timer 104 controls the state of the host computer pair 34A-34B which are interconnected by lines 100, 102 as well as controlling the switching of the universal line switch 106A whose output is provided via modem 156A to telephone line 158, by way of example, and therefrom to modem 156B and to the associated terminal controller 80C and its associated keystations 166 and 168, by way of example (FIG. 1).

Referring now to FIGS. 4A and 4B, the function of the watchdog timer 104 shall briefly be described. The configuration illustrated in FIG. 4A comprises the two host computers 30A and 30B by way of example or 34A and 34B depending upon the node configuration, the watchdog timer 104, and the universal line switch 106 for the configuration of node 30 and 106A for the configuration of node 34, the only difference being in the number of lines being serviced by the universal line switch. FIG. 4B is a graphic illustration of a timing diagram illustrating the timing cycle of the watchdog timer 104. Suffice it to say that the watchdog timer 104 is an electronic switch which preferably provides a continual monitor of the main and stand-by computers 30A and 30B, respectively, by way of example, within a dual processor system arranging to interchange their roles as and when necessary. Of course, if such a dual processor system is not desired, then the watchdog timer 104 may be omitted as is true for any other stand-by equipment. However, in a real time communications service it is preferably preferred that instantaneous back-up be available. Preferably, the watchdog timer 104, when employed, connects each processor or host computer 30A, 30B using an asynchronous serial line interface as well as providing control signals to the universal line switch 106 or 106A which preferably enables common communication lines to be routed to the processor 30A or 30B which is currently considered the main or active processor. In addition, if desired, the watchdog timer 104 can be employed to signal the universal line switch 106 or 106A when both main and stand-by processors 30A and 30B or 34A and 34B are intended to be functional simultaneously so that the total communication load could be shared between them if desired. The watchdog timer 104, which preferably utilizes conventional logic components and itself contains power supply and battery back-up unit, preferably communicates with the processor pair 30A-30B or 34A-34B using a polling mechanism such as illustrated in FIG. 4B. Thus, at a predetermined time in its timing cycle, the watchdog timer 104 sends a character to each processor 30A and 30B or 34A and 34B. These characters which may be switch selectable, are preferably, by way of example, an L to the active or live processor 30A or 34A and an S to the stand-by processor 30B or 34B. The watchdog timer 104 then preferably generates a delay followed by a window period within which the watchdog timer 104 expects to receive back from each processor 30A and 30B or 34A and 34B the same character that was sent. Any error either in time, that is if the character was returned outside the window interval or not at all, or in content, that is if the wrong character were returned, indicates a failure of that processor 30A or 30B or 34A or 34B. If the stand-by processor has indicated a failure, that is processor 30B or 34B, the watchdog timer 104 merely notes this condition and provides some type of visual alarm so that it may be corrected. If, however, it is the active or main processor 30A or 34A which has indicated a failure condition, and the stand-by processor 30B or 34B has not indicated a failure condition, an alarm is preferably provided and an exchange of roles between the active processor and the stand-by processor is automatically triggered. This is accomplished by the watchdog timer 104 preferably swapping the transmitted characters so that the previously designated stand-by processor 30B or 34B would then receive the active processor test character and the previous active or main processor 30A or 34A would receive the designated stand-by processor test character. The poll test characters when received by the processors 30A-30B and 34A-34B would preferably interrupt to trigger various programming checks which ultimately determine the response. The watchdog timer 104 then preferably attempts a periodic reload of the failed processor. The desired poll frequency and window length graphically illustrated in FIG. 4B is preferably determined by various switch settings on the conventional logic boards with the watchdog timer 104 preferably not permitting switching to a failed processor nor allowing too frequent switching between systems so as to prevent oscillation should both processors have intermittent faults. By way of example, the maximum poll rate for the watchdog timer 104 in the slow cycle may be 2.8 seconds and in the fast cycle 300 milliseconds with a minimum poll rate being set as a function of the baud rate selected. Similarly, the maximum window length in the slow cycle may be 800 milliseconds and in the fast cycle 100 milliseconds with a minimum window length in the slow cycle of 8 milliseconds and in the fast cycle 1 millisecond, by way of example. In addition, the reload frequency may have a maximum of 1 minute 40 seconds and a minimum of 1 second by way of example with a 1 millisecond reload pulse and a corresponding transmission speed having a maximum of 9600 baud and a minimum of 75 baud, by way of example. With respect to the universal line switch 106 or 106A, a typical such universal line switch is illustrated in FIGS. 5A and 5B. Thus FIG. 5A diagramatically illustrates a universal line switch comprising a plurality of switch networks 200 each of which, as shown and preferred in FIG. 5B, which illustrates a typical switch network 200, is a relay network capable of switching, in the asynchronous mode, 8 duplex lines or in the synchronous mode, 16 lines, with control signal buffers 202 being provided for the control signal input from the watchdog timer 104. In addition, as illustrated in FIG. 5A, by way of example, an automatic/manual mode may be provided for the universal line switch 106 in order to manually override the coantrol signal input from the watchdog timer 104 if desired. In addition, the configuration in FIG. 5A illustrates daisy chaining of the control interface which may be employed depending on the number of lines to be switched with the understanding that each switch network 200 preferably is capable of switching 8 duplex asynchronous lines. Thus, if 16 asynchronous duplex lines are to be switched then two switch networks 200 would be needed whereas if 96 duplex asynchronous lines are to be switched then 12 such switch networks 200 would need to be employed in which instance they would preferably be daisy chained for purposes of size considerations primarily. FIG. 5B illustrates schemeatically the universal line switch 106, illustrating a typical switch module network 200 therein. The contents of the schematic drawing of FIG. 5B is essentially self-explanatory and will be readily understood by one of ordinary skill in the art. Accordingly, it will not be described in any greater detail hereinafter.

Referring now to FIGS. 6A through 6B and 7A through 7K, a typical preferred terminal controller 80 of the present invention, which interfaces the various associated subscriber keystations with the balance of the system network 20, shall now be described in greater detail. As will be described hereinafter in discussing the system operation, it is the address of the respective terminal controllers which are inserted in the subscriber control page list rows to designate recipients of the alert communication messages to be originated and transmitted by various subscriber contributors in the network 20. Moreover, as will also be described hereinafter, it is the terminal controller 80 and not the node computers at nodes 22 through 38 which stores the alerts page for the subscriber recipients associated with that terminal controller 80. Referring initially to FIGS. 6A and 6B which provide an overall system functional block diagram of a typical terminal controller, such as terminal controller 80A, employed in the alert communication system network 20 of the present invention, the terminal controller 80A is preferably a communications oriented intelligent terminal utilizing a conventional microprocessor 300, such as an Intel 8080A micro-processor with its conventionally associated supporting peripherals, with the terminal controller 80A preferably being functionally divided into an input/output portion 302, the central processing unit 300 and its associated peripherals, a display generator portion 304 and conventional bus switching circuitry. The terminal controller 80A is employed to request, retrieve and supply information to and from its associated node 22 through 38 with the terminal controller 80A which is illustrated in FIG. 6A, 6B and 7A through 7K, by way of example, being selectable so as to be usable either as a terminal controller capable of providing an alerts communication message along with the ability to request and retrieve the information from the system or one which is solely capable of requesting and retrieving information from the system without having the capability of providing alert communication message control. Thus, in both instances, the terminal controller 80A includes five conventional display memories or RAMs 310, 312, 314, 316 and 318; however, in the mode in which alert communication message control is provided, then one of the display memories, such as display memory 318 by way of example, would be employed to maintain a local alerts page, such as illustrated in FIG. 8D in which instance, the terminal controller 80A could only support four keystations. However, if the terminal controller 80A is operated in the mode in which the alert message communication control is not desired, that is where no alert page is to be locally maintained at terminal controller 80A, then display memory 318 may be used to support a fifth keystation. As will be described in greater detail hereinafter, the two modes of the terminal controller 80A are switch selectable. Of course, if desired, this mode selection feature could be omitted and the terminal controller 80A could solely be used in the mode in which display memory 318 would be dedicated to local alerts page message storage. In addition, as shown and preferred in FIGS. 7A through 7K, the terminal controller 80A may have a plurality of selectable alerts pages, such as eight pages designated LSTA through LSTF. For purposes of explanation, however, it shall be assumed that only one such alerts page or list namely LSTA is employed. As will be described in greater detail hereinafter, a subscriber contributor through an associated terminal controller 80 and the associated node 22 through 38, can direct specifically formatted alert communication messages to other designated terminal controllers 80 which will cause an alert message "SEE ALERTS LIST" to be displayed, for example, on row 14 of the display at each keystation associated with the designated terminal controller or controllers, and the text of the alert communication message will be written to an alerts page maintained in each fifth display RAM 318. This alert communications message will preferably appear as a page of data to the alert page LSTA in the example to be described herein. By way of example, the alert communication message originated by the subscriber contributor is provided to the various designated terminal controller 80 in the network 20 in the following format: SOH ADRI STX LSTA * DATA ETX BCC, where SOH is a start of header, ADRI is the controller identifier, STX is the start of text, LSTA is the alerts page number identifier, * is the unique identifier used to define an alert, DATA is the alert communication message comprising up to a total of 64 characters as will be described in greater detail hereinafter with reference to FIG. 8B, ATX is the end of text, and BCC is the sum check. The terminal controller 80 in the alert communication message mode, will preferably detect the above alert message as being an alert message by the last character of the page name and the unique character following the page name. Thus, if the terminal controller is set up for the page name LSTA and it receives an alert for the page name LSTB then it would escape that message and only accept alerts for the page name or names that it is set up for. Preferably, the aforementioned alert message is structured such that if it is directed to a terminal controller that is not in the alert message communication mode then the terminal controller will escape the message. As will be described in greater detail hereinafter, each alert received by the terminal controller will be written to the local alerts page stored in the terminal controller 80 and an alert message will be flashed on row 14 of each keystation associated with that terminal controller 80. The alerts page or list will be updated such that the last message will always preferably be displayed on row 3, as illustrated in FIG. 8D, and any previous messages will be rolled down by one row with the oldest alert message appearing on the bottom most row. Moreover, the updating of the alerts page for that terminal controller 80 will cause any keystations currently displaying that alerts page to be updated accordingly. The subscriber keystation associated with that terminal controller 80 may display the alerts page in one of three fashions; namely by retrieving the page LSTA which causes that page to be instantaneously dumped from the alerts page RAM 318; the video feed from this RAM 318 may alternatively be fed into one or more slave screens 82B which would enable the alerts page to be displayed at all times; or the video feed from the alerts page RAM 318 could be connected to a video switch which would enable the subscriber to instantaneously switch between his regular display and the alerts page display. Preferably, the alerts page once on display may not be cleared or altered by the subscriber, with the only keyboard operations available when the alerts page is on display preferably being reset and print. In addition, preferably, while the alerts page is on display, all row 14 alert messages will be directed to the screen 82B.

As shown and preferred in FIG. 7B by way of example, the terminal controller 80A preferably includes eight external link switches 400, 402, 404, 406, 408, 410, 412 and 414 with switches 400, 402 and 404 preferably being utilized to select the page name of the alerts page, for example 0 equals LSTA, 1 equals LSTB and so forth for the eight possible combinations provided by the three switches 400 through 404. Switch 410 is preferably used to select the mode of the terminal controller 80A with the terminal controller 80 supporting five keystation and not, thereby, capable of local alerts page storage when switch 410 is closed and with the terminal controller 80A supporting four keystations and local storage of the alerts page in the fifth display RAM 318 when switch 410 is open. Updates to a page on display on the screen may be enabled to flash for five seconds after its reception at the terminal controller when switch 408 is open. With respect to switch 406, this preferably determines hard copy printing from printer 150A, for example, with the hard copy printer 150A being dedicated solely for the printing of alert communication messages as they are received when switch 406 is open and with this feature being disabled when switch 406 is closed. Once this feature has been selected, however, it may then be enabled or disabled only via the main keystation such as keyboard 1 in the example of FIGS. 7A through 7K. With respect to switch 412 this switch preferably determines whether the link code will be derived from a switch block 416 or off the line. Thus, by way of example, if switch 412 is open, the link number or code will be derived off the line whereas if switch 412 is closed the link code or number will preferably be derived from the position of the various switches comprising switch block 416. By way of example, with respect to the use of switches 400, 402 and 404 to select the available alert page or list identifiers, LSTA may correspond to switches 400, 402 and 404 being closed, page LSTB may correspond to switch 400 being open and switches 402 and 404 being closed, page LSTC may correspond to switches 400 and 404 being closed and switch 402 being open, page LSTD may correspond to switches 400 and 402 being open and switch 404 being closed, switch LSTE may correspond to switches 400 and 402 being closed and switch 404 being open, page LSTF may correspong to switches 400 and 404 being open and switch 402 being closed, page LSTG may correspond to switch 400 being closed and switches 402 and 404 being open, and page LSTH may correspond to switches 400, 402 and 404 all being open. With respect to the aforementioned printer 150A, it is preferably a conventional hard copy printer such as one running at 30 cycles per second with the input line thereto being at 120 cycles per second in which instance the terminal controller 80A preferably buffers up to 11 alert communication messages for output to the printer 150A with the effective buffering level being on the order of magnitude of 13 or 14 alert communication messages since the printer 150A would be outputting as new alert communication messages are coming in. Of course, if desired, a 1200 baud printer could be used if a more rapid output rate were desired.

Referring again to FIGS. 6A and 6B, the input/output 302 of the terminal controller 80A preferably consists of nine input/output ports which transfer data between the various peripheral devices and the central processing unit 300, with these peripheral devices consisting of either four or five keyboards depending on the mode of the terminal controller 80A, a modem 126B associated with the terminal controller 80A and the printer 150A. The central processor portion preferably comprises the microprocessor 300 along with the associated conventional interrupt control logic 350, the U.V. erasable memory 352, a volatile memory 354 and the address decoding logic 356. The purpose of the microprocessor 300 in the terminal controller 80A is to control the input/output portion 302 of the terminal controller 80A, interpret the information coming from the various peripheral devices, write or read the information to the display generator memories 310 through 318 and output this information to the devices. These functions are preferably achieved in a sequence dictated by the program memory. An example of such a typical control program for the Intel 8080A microprocessor 300 in the terminal controller 80A, assuming the terminal controller 80A is used in the mode in which the RAM 318 stores the alerts page, is given below in Table A, with this exemplary control program being written in Intel 8080 assembler language:

(see attached program listing)

The display generator portion 304 of the terminal controller 80A preferably comprises a video sync generator 360, safe title area decode logic 362, a display address counter 364, the previously mentioned display memories 310 through 318, five associated character generators 366, 368, 370, 372 and 374, respectively, and five data/sync combiners 376, 378, 380, 382 and 384, respectively. The purpose of the display generator portion 304 of the terminal controller 80A is to produce a television sync signal, inform the central processing unit 300 when it may access the display memory 310 through 318, convert the data stored in the display memories 310 through 318 into intelligible form and produce a composite video signal for display on the respective screens 82B of the keystations associated with the terminal controller 80. The bus switching network preferably conventionally consists of transceiver devices whose purpose is to connect the input/output portion 302 or the display generator portion 304 to the central processing unit address or data bus.

Referring now to FIGS. 7A through 7F, the input/output portion 302 and central processing unit portion of the terminal controller 80A shall now be described. As shown and preferred in FIG. 7B, the input/output portion 302 of the terminal controller 80A preferably comprises three conventional parallel ports 450, 452 and 454 such as conventional Intel 8255 parallel ports, and two conventional Universal Synchronous Asynchronous Receiver and Transmitters or USARTS 456, 458 (FIG. 7A) such as Intel 8251 USARTS. The purpose of the parallel ports 450, 452 and 454 is to preferably read in the link and poll number, parallel data from the various associated keyboards, the necessary alert message control information via switchbank 400-414 and output the buzzer signal to the respective keyboards 82A. Each of the Intel 8255 parallel ports 450, 452, 454 is a programmable interface which has, by way of example, 24 input/output lines. Preferably, each of these interfaces 450, 452 and 454 is programmed by the microprocessor 300 to function in the appropriate mode, such as one which enables each group of twelve lines to be programmed in sets of four for input or output. The respective responsibilities of the interfaces 450, 452 and 454 may readily be determined by reference to FIG. 7B with a previously noted, interface 454 being responsible for keyboard 5 and/or associated display RAM 318 via switchbank 400-414, inclusive. It should be noted that when the absolute address of any one of the display memories 310 through 318, inclusive, is asserted, this address is decoded to select a particular display memory 310, 312, 314, 316 or 318. This may represent the upper four bits of the address bus, with the lower ten bits of the address bus, by way of example, used to select a particular location within that display memory 310-318.

Preferably, to transfer data to or from the parallel ports 450, 452 and 454, the microporcessor 300 must issue a chip select signal level SELCH1, SELCH2, or SELCH3, with the chip select signal being a decode of the lower eight bits of the CPU address bus. The CPU 300 must also select which port will input or output data to the CPU data bus with this being accomplished by the A0 and A1 address lines of the CPU address bus. With respect to the USARTS 456 and 458, these are programmable communication interfaces with interface 456 preferably being programmed for eight bit asynchronous operation and being used to receive and transmit serial data to the modem 126B. Again, before the USARTS 456 or 458 can operate they must receive a chip select signal which, with respect to interface 456 is a decode of address D0. Interface 458 is preferably used to transmit data to the printer 150A. The I/O read and I/O write lines from the CPU 300 are preferably used in conjunction with the chip select signal to determine the direction of the data for interfaces 456 and 458. In addition, the CPU address A0 line informs the USARTS 456, 458 that the data bus has either a data word or control/status word. The baud rate clock which is shown as illustratively being connected to the USARTS 456 and 458 is preferably selected so as to be 16 times the required baud rate for interface 456 and 64 times the required baud rate for interface 458. The operation of interface 456 is as follows. When a character has been shifted in from the modem 126B, interface 456 buzzes the receiver ready line RXREADY high to inform the CPU 300 that a character is available. The CPU 300 then issues a chip select signal and an I/O read signal to take the character with this operation causing the receiver ready line to then go low in readiness for a further character. When the CPU 300 wishes to transmit a character, it must first receive a transmitter ready signal TXREADY. The CPU 300 then issues a chip select signal and an I/O write signal to load a command word which asserts the request to send line. When this line is asserted, a one-shot 462 is asserted for a preset period, such as approximately 40 milliseconds in which time the flip-flop 464 is clocked returning the clear to send line or CTS to interface 456. This informs interface 456 that data may be transmitted. It should be noted that preferably the operation of USART 458 is identical with that of USART 456 with the exception that USART 458 is preferably only used for transmission of data to the printer 150A. The aforementioned baud rate generator clock preferably consists of a pair of conventional counters 466 and 468 such as conventional 74LS161 counters which divide the CPU clock by 28. The output of this counter 466-468 is preferably then divided by 2 in flip-flop 470 to provide a symmetrical input for a divide by 1.5 flip-flop 472.

Referring now to FIG. 7C, the microprocessor configuration for the terminal controller 80A shall briefly be described in greater detail. Thus, as shown in FIG. 7C, the Intel 8080A microprocessor 300 conventionally requires a clock generator 480, such as an Intel 8224, and a system controller 482, such as an Intel 8228. The clock generator 480 conventionally produces the timing signals required by the microprocessor 300 while the system controller 482 conventionally decodes data from the microprocessor 300 into single command lines such as IOR, IOW, etc, and gates data between the CPU 300 and the data bus. The microprocessor 300 functions in a conventional manner to execute the illustrative control program provided above in Table A. Suffice it to say that the clock generator 480 is driven by a 14.3181 megahertz crystal which after conversion of TTL level, is fed to the display generators to produce all the required display timing signals and is further also divided by 9 within the clock generator 480 to produce the phase 1 and phase `signals to the microprocessor 300 thereby providing a microprocessor 300 with a 628 nanosecond cycle time, by way of example. As further shown and preferred in FIG. 7C, all of the peripheral devices conventionally communicate with the CPU 300 under interrupt control which is conventionally achieved by programmable interrupt controllers 484, 486, such as Intel 8259 interrupt controllers. The various interrupt lines illustrated in FIG. 7C are labelled STAEND which informs the CPU 300 that it may write to the display memories 310 through 318, inclusive, START which informs the CPU 300 that it must stop writing to these display memories 310-318, RXREADY 1 which informs the CPU 300 that a character is available from the modem 126B, TXEMPTY 1 which informs the CPU 300 that it may drop the request to send or RTS line TXREADY 1 which informs the CPU 300 that it may load a character into the USART 456 for transmission to the node 30 via the modem 126B, TXREADY 2 which informs the CPU 300 that it may load a character into the USART 458 for transmission to the printer 150A, and KBSTID which informs the CPU 300 that a key has been depressed on one of the active keyboards. As soon as the interrupt controller 484 or 486 receives an interrupt on any input line, it preferably asserts the interrupt IN line on the CPU 300 and the device that caused the interrupt then waits for acknowledgement from the CPU 300.

The aforementioned address decoder 356, as shown and preferred in FIG. 7C preferably comprises an address decoder 356A, such as a conventional 74LS154 decoder which defines which 1 K block of memory is to be accessed, by way of example, address decoder 356A being a 4-16 line decoder, and a second decoder 356B, such as a conventional 74LS42 decoder, which decodes the lower eight bits of the address lines to provide the various peripheral chip select signals illustrated in FIG. 7C. Decoder 356B is, by way of example, a 4-10 line decoder.

Referring to FIG. 7E, the program memory 352-354 as was previously mentioned consists of up to 6 K by 8 bits of UV erasable memory 352 and 1 K by 8 bits of scratch pad or random access volatile memory 354. The PROM memory 352A, 352B and 352C preferably comprises 3 conventional 2 K by 8 bit PROMs, such as conventional 2716 PROMs, and contain the control program for the microprocessor 300 such as the exemplary control program described above in Table A.

The random access memory or scratch pad memory 354 preferably comprises 2 RAMs such as conventional 2114 RAMs 354A, 354B each of which has a capacity of 1,024 by 8 bits. The balance of the circuitry of FIGS. 7A through 7F is believed to be essentially self-explanatory to one of ordinary skill in the art based on the foregoing description and will not be described in greater detail hereinafter.

Referring now to FIGS. 7A through 7K, the disclosure in the display generator portions 304 of the terminal controller 80A shall now be described in greater detail. Suffice it to say that the disclosure of the display generator portion 304 preferably contains all of the required circuitry to produce five independent CRT display signals, each consisting of 1,024 characters. However, as was previously mentioned, in the presently preferred mode of the terminal controller 80A when it is enabled to store alert pages in display memory 318, no fifth independent CRT display signal is provided. The display generators can preferably be separated into a TV sync portion, a safe title area decoder portion, a memory addressing and character generator timing portion, a display memory portion and the associated character generators and combiners. The purpose of the sync generator is to produce a non interlaced horizontal and vertical composite sync signal, to synchronize the horizontal and vertical time bases contained in the associated television monitor displays 82B; the purpose of the safe title area decoder is to define an area where the data will be displayed on the TV monitor screen 82B, the memory addressing and character generator timing determine whether the display memories 310-318 are addressed by either the CPU address bus or the display generator address bus, with the display generator address bus having priority over the CPU address bus. The display memories 310-318 each preferably consist of pairs of static random access memories, such as Intel 2114 Static Random Access Memories each having 1,024 by 4 bit capacity, and the character generators 366 through 374, where applicable, conventionally function to provide the video display of the data from the associated display memory 310-318. The operation of the display generator portion 304 of the terminal controller 80A would be readily apparent to one of ordinary skill in the art with reference to FIGS. 7H through 7K and the foregoing description including the exemplary control program. Suffice it to say that logic elements A1, B1, C1 and K4 form a synchronous divider which divides the CPU clock by 919 producing a load signal for itself every 64.18 microseconds with F1-1 also being included at this time and after the duration of 86 clocks, F1-3 is clocked producing a signal with a repetition rate of 64.18 microseconds and a pulse with of 6.1 microseconds which is the horizontal sync signal. This signal is used to produce the vertical sync signal utilising elements G1, H1, J1, J2 and K1 which form the vertical sync generator. The vertical and horizontal syncs are gated at K2-13 and 12 to produce a composite sync signal at K2-11. Similarly, the safe title area is conventionally obtained by decoding the required clock and line counts from the sync generator and although the display generator does not contain a unique character or row counter, the horizontal and vertical safe title areas are used to determine the character and row counts producing, by way of example, a horizontal safe title area of 44.69 microseconds in every duration of 640 clocks. The vertical safe title area is also conventionally obtained in a similar manner and is used to terminate the vertical display area as well as to inform the CPU 300 when it may write or read the display memories 310-318, with the CPU 300 not being enabled to access the display memories 310-318 during the display period. This is achieved by interrupting the CPU 300 at the beginning and end of the vertical safe title area. When the vertical safe title area is active, selectors H7, J7, and K7 are switched to route the output of the display address counter H6, J6 and K6, represented collectively by reference numeral 364, to the display address counter bus AD0-AD9 with the display address counter also being released at this time. The horizontal and vertical safe title areas are gated together at K2-9 and 10 to produce VHSTAL which is used to control the character generator display sequence. When VHSTAL is active, J4-5, J5 and K5 are released with J5-3 going high on the next dot clock and producing the latch signal to the address latches in the character generataors 366 through 374 which are also labelled as C6, D6, E6, F6, and G6. Therefore, the data loaded into the five character generators 366 through 374 will be the contents of location 0 from all five display memories 310 through 318; that is, the first character to be displayed. Of course, the above explanation is based on the assumption that five keyboards and the resultant keyboard displays are controlled by the terminal controller 80A. However, as previously described, in the preferred mode for controller 80A, only four keyboards are controlled with display memories 310 through 316 being associated respectively with these keyboards, and with display memory 318 being solely dedicated to storage of the alert page for the terminal controller 80A. As was stated above, it is believed that no further explanation of the schematic diagrams of FIGS. 7A through 7K is needed other than heretofore provided. Suffice it to say before going on with the description of the system operation, that the various line transmissions between the nodes or PDP11 host computers and the terminal controllers 80 take place at 1200 baud in an asynchronous start/stop mode with the characters being 8 bit ASCII, that is 7 data bits plus a parity bit, with there being one start bit and one stop bit and with the subscriber lines all being full duplex. The data messages in both directions between the terminal controller 80 and the node computer 30A for example, are preferably checked using horizontal character parity and a longitudinal check character following each data message. In addition, the system network 20 preferably employs polling at each node 22 through 38 with a system parameter defining how many terminal controllers 80 may be polled by an associated node for each line with, for example, the minimum number being 1 and the maximum number being 8. Thus, the host computer preferably polls all defined controllers 80 on the line associated therewith in turn to check if they have any subscriber queries or messages. The node host computer is also able to send messages or updates to the terminal controllers 80 even when no query has been received with these messages being transmitted with a controller addressing sequence as a header which is recognised by the addressed controller 80 and the attached message is accepted. The terminal controller 80, in turn, poles the various keystations associated with it to determine if any of the keystations has a query which may subsequently be transmitted to the host computer at the node, such as node 30, when poled by the host computer.

The operation of the system following the present invention in providing an alert communication message shall now be described below with reference to FIGS. 8A through 8E in which it shall be described how a subscriber contributor may create both variable content lists of designated recipients as well as variable content alert messages for these recipients who may be located at different nodes 22 through 38.

"System Operation"

As was previously mentioned, the presently preferred alert communication system 20 of the present invention can be employed for providing any type of alert communication message throughout the world-wide network 20 with the alert communication message being originated by a particular subscriber at the subscriber keystation 82, for example, wherein the originating subscriber 82 may selectively designate other subscriber keystations through their associated terminal controllers in the network 20 to receive the alert communication message transmission. In the example of FIG. 1, three typical terminal controllers 80A, 80B and 80C, are illustrated. For purposes of explanation of the operations of the system 20, it shall be assumed that the subscriber keystation 82 associated with terminal controller 80A designates only selected controllers at the various node locations 22 through 38 to receive a given alert communication message. Furthermore, as was also previously described, although the alert communication message may be used for various purposes, such as commodities information, money rate information, securities information and information relative to the shipping market, as well as other purposes which will readily occur to one of ordinary skill in the art, it shall be assumed that the alert communication message relates to shipping information such as space availability on a ship or tanker which the originating subscriber 82 may wish to either purchase or sell as available space to other selected subscribers within the network 20. Thus, for example, shipbrokers can ensure that their clients are kept up to date with information whereas charterers, owners and broker subscribers can all have convenient access to essential market data such as enquiries and fixtures. In addition, the subscriber, such as subscriber 82, via his associated keyboard 82A may insert desired market report information. As will be described in greater detail hereinafter, when the contributing originating subscriber 82 has created the alert message, the subscriber then transmits this alert communication message to the various subscribers contained on the subscriber's control page which has been stored locally at each of the nodes 22 through 38 in the network 20. Referring now to FIGS. 8A through 8C, a typical control page for providing shipping market alert communication messages shall now be described. Each subscriber who is a contributor or originator of data is allocated one or more control pages in the various associated memories of the host computers located at the nodes 22 through 38, respectively. As illustrated in FIG. 8A, each control page, by way of example, is allocated 10 horizontally displayed lists, labelled A through J respectively, each of which may contain up to 10 designated subscriber recipient network addresses. With respect to these addresses, each network address is preferably made up of a letter prefix which designates the node 22 through 38 at which the recipient is located and a four position unique address within that node. Thus, for example in FIG. 8A, shipping list A contains only one subscriber recipient designated Z0312 indicating that that recipient is connected to node 26 and has identification number 0312. Similarly, with respect to shipping list F by way of example, there are subscriber recipients designated which are associated with node 36, namely those designated T1020 and T1200, associated with node 38, namely that designated H0056, and associated with node 22 namely those designated G1222, G0025 and G0965. The content of each of the respective 10 lists A through J in a control page is readily variable by the contributor or originator and only by that contributor or originator. Moreover, a given list may designate subscribers at any of the nodes 22 through 38 within the network 20 and, thus, may contain any desired mix of recipients without being confined to a particular node. As will be noted in FIG. 8A, lists can be left blank and contain no designated addresses, or, if desired, a given designated recipient can subsequently be blanked out by the subscriber contributor without affecting the balance of the contents of the list, such as illustrated in list E of FIG. 8A where the middle recipient of the three designated recipients is illustrated as subsequently being deleted which would result in a blank space ultimately existing between the other two designated recipients in list E. These various designees are altered in the manner described below with respect to the insert feature of the system 20. Referring now to FIG. 8B, the mechanism for generating an alert communication message is as follows. First, the contributing subscriber, for example subscriber 82, must set up the addresses of the desired recipients for each of the up to 10 lists A through J. Of course, these lists could have been pre-designated at a prior time and, if desired by the contributing subscriber, need not be changed until such time as it is desired to change one or more of the potential recipients for a particular alert communication message. Assuming the contributing subscriber wishes to create a list or to change a previously created list, the subscriber must first display the control page on the display screen 82B of the keystation 82. As will be described in greater detail hereinafter, the control page is divided into rows and columns and the subscriber indicates on his keyboard, by row and column, that information which is to be inserted or changed with the overriding requirement being that the address, as previously mentioned, must contain an identifier for the node as well as a four digit identification code for the particular recipient controller 80 at that designated node. After this has been accomplished, or assuming the originating subscriber is satisfied with the previously created control page, in order to generate an alert communication message an originating subscriber 82 must have the control page on display on the display screen 82B. The subscriber 82 then depresses an insert key on keyboard 82A followed by an alert message prefix which in the example of FIG. 8B is *, followed by a list identifier identifying one or more of the 10 potential lists displayed on the control page as recipients for this particular alert communication message, followed by a delimiter, such as a "/" which delimits the control information from the text information, and thereafter followed by a predesignated length character text string which comprises the alert communication message. Preferably, the alert text string may not, by way of example, exceed 59 characters out of a maximum of 64 potential characters in the row. Thus, if the alert list specifier exceeds more than one character, then the amount of potential characters available for the alert text string will decrease proportionately. With respect to the alert list specifier, the list identifiers may be specified singularly as illustrated in FIG. 8B or in ranges such as A-D meaning A, B, C, D or both such as AC-EG meaning list A, C, D, E and G. For example, this alert communication message is inserted on row 15 of the displayed control page. To transmit the alert to the designated subscriber recipients, the originating subscriber 82 must then depress the transmit button located on the keyboard 82A. The keyed in alert text string containing the alert communication message is then transmitted from the subscriber 82, through the terminal controller 80A, through the modems 126B and 126A and the telephone line 122, to the concentrator 54, therefrom to the associated node 30. Node 30 then verifies the correctness of the alert communication message and, assuming the message is verified, node 30 performs several functions. One of these functions is that an echo message is transmitted back to the concentrator 54 and therefrom through the terminal controller 80A to the originating keystation 82 where the alert communication message is displayed, for example, on row 13 of the control page such as illustrated in FIG. 8B. In addition, the node 30 determines whether there are any terminal controllers associated with node 30 which have been designated in the alert list specifier associated with the alert communication message and transmits this message to those terminal controllers so designated. Furthermore, node 30 transmits the alert communication message to all of the other nodes 22 through 38 in the system network 20. Each of these nodes 22 through 38, then independently determines if there are any terminal controllers associated with that particular node which have been designated in the address list in the respective stored control pages which correspond to the alert list specified in the alert communication message being transmitted by subscriber 82. If so, then the respective node transmits the alert communication message to the designated controllers, for example if terminal controller 80B and 80C were designated in the alert list specified for the particular alert communication message, then node 22 would transmit the message to terminal controller 80B and node 34 would transmit the message to terminal controller 80C. As further illustrated in FIG. 8C, the control page may also include a subscriber predesignated message which may subsequently be included as a portion of a subsequently generated alert communication message. In order to create this pre-defined text, the subscriber contributor must first retrieve and display the control page and thereafter depress the insert key on keyboard 82A and then the designator for such a pre-defined text such as for example the letter S followed by a delimiter such as the aforementioned "/", thereafter followed by up to 19 characters of pre-defined free format of text. It should be noted that this pre-defined text during its creation does not contain an alert list specifier since at this point the message is merely to be stored for subsequent transmission and is not being immediately transmitted to subscriber recipients. In order to store this pre defined text, the subscriber contributor depresses the transmit key on the keyboard 82A which causes the pre-defined text message to be transmitted through the terminal controller 80A to the node 30 which verifies the message and echos it back to the originating subscriber 82 through the concentrator 54 and the terminal controller 80A resulting in a display at row 14 of the control page being displayed on display 82B. Node 30 also transmits this message to each of the other nodes 22 through 38 in the system which store this message on the respective control page in their associated local storage. If the subscriber now wishes to incorporate this pre-defined text in an alert communication message, the subscriber creates the alert communication message in the same manner as previously described with reference to FIG. 8B with the exception that after the first delimiter following the alert list specifier, the subscriber inserts the code indicating pre-defined text which is the letter S followed by a subsequent delimiter followed by additional alert text. The second delimiter is identical to the first delimiter which is a "/". It should be noted that the length of permissible alert text string is still a maximum of up to 59 characters including the expanded length of the pre-defined text. Thus, for example, if the pre-defined text contains 19 characters, then only a maximum of an additional 40 characters may be included in the additional alert text being created, assuming that there is only one alert list specified with a proportionate reduction in the number of available characters occurring, as previously mentioned, as the amount of specified alert list increases. When this alert communication message has been created, the full expanded message is transmitted throughout the network and is echoed back to the originating subscriber 82 for display on row 13 of the control page as was true with respect to the previous description of an alert communication message. It should be noted that even though a pre-defined text has been created, the originating subscriber need not use it in an alert the "SEE ALERTS PAGE" visual display remains until cancelled by the subscriber by depression of the reset key on keyboard 82A. It should be noted that the alert communication message may contain information referring to a more complete page containing the data to which the originator would like the recipient to refer. Such a typical page of text data is illustrated in FIG. 8E. As previously mentioned, a printer 150 for example is associated with each terminal controller 80A for example, which may normally be utilized by any keystation 160, 82, for example, in order to print ordinary pages as exemplified by FIG. 8E by depression of the print button located on the respective keyboards 82A; however, if it is desired to print alert communication messages such as would normally be contained in the alerts page, this can preferably only be accomplished by a master control keystation associated with each terminal controller 80, such as for example by keystation 82.

It should be noted that as previously mentioned the printer 150A, for example, may be set to automatically print out alert communication messages as they arrive or may be set in the manual mode to print information pages on command. To enable the automatic print out of incoming alert communication messages, the associated keyboard 82A on the main keystation designated keyboard number 1, is employed. Thus, to enable the printer 150A to automatically print out incoming alert communication messages directed to terminal controller 80A, the reset button, the print button and the enable button are depressed on the keyboard 82A of the master keystation. Similarly, to disable these automatic print outs and return to the manual mode, the reset button, print button and disable button on the same keyboard 82A are depressed. Preferably, when the automatic print function for incoming alert communication messages is enabled, this information will be displayed on the alerts page such as by the use of the characters PE representing print enabled on line 1 of page LSTA. As was previously mentioned, selection of this automatic print-out function disables any regular hard copy printing of information messages until the printer 150A has been returned to the manual mode. To print any display of information messages in the manual mode, any of the keystations may accomplish this by passing the PRINT key on the associated keyboard and the display will be printed exactly as it appears on the screen at the time the PRINT key is depressed. Nevertheless, the page on display will continue to update and other pages could be selected without affecting printed data.

In addition, as shown and preferred in FIG. 8D, the reception of an alert communication message by the associated terminal controllers 80 to which the message is designated, preferably causes simultaneously the message "SEE ALERTS PAGE" to be flashed on each screen associated with the terminal controllers 80 receiving the message and causes the time of receipt by the nodes 22 through 38 to be displayed adjacent to the received alert text in the alerts page. By way of example, in the system disclosed herein, a subscriber contributor may direct an alert communication message to between 2 and 25 subscribers at a time.

Referring once again to FIG. 8E, as was previously mentioned, a displayable page is divided into insert rows and insert columns with the subscriber contributor inserting information to a page, whether it be a control page or a page of data, by insert row and insert column designation. Thus, for example, in FIG. 8E the insert rows are labelled respectively 1, 2, and the letters A through J, with the insert columns being labelled K through P. Preferably, with respect to the ordinary page of text data illustrated in FIG. 8E, the page is limited to a 64 character line length with rows 1 and 2 being fixed format heading rows and with rows A through J being rows in which subscriber originated data can be inserted. Information is preferably inserted to the page by nominating the page area to be updated or to which the information is to be inserted by using the two designated co-ordinates for the appropriate line and column. For example, in the illustration of FIG. 8E, the co-ordinate AK would nominate the position for "BROOKLYN". In order to insert information on a given page, the page on which the information is located is retrieved by the subscriber by designating the appropriate page code on the associated keyboard 82A and this page is then displayed on the screen 82B. The subscriber then depresses the INSERT button on keyboard 82A and a flashing cursor preferably appears in the lower right-hand corner, for example, of the screen 82B. The subscriber then keys in the two co-ordinates which designate the row and column of the information to be inserted, followed by the new or updated information to be inserted in this location and thereafter depresses the TRANSMIT button or key on the keyboard 82A. This subsequently results in the new update information appearing in this designated position or location. In order to insert more than one piece of information for a given row, this may be accomplished by separating each item with a semi-colon. The cursor can be employed to correct incorrect information in conventional fashion. Free format pages, that is pages which are not divided into several columns, are preferably defined with a single column and have a maximum line length of 64 characters, for example, over 10 insertable rows with semi-colons not being necessary to separate items of information. To delete all the information on a page, the page is retrieved as stated above, the INSERT key on the keyboard 82A is depressed, the word DELETE is keyed in and the TRANSMIT key or button on the keyboard 82A is depressed. This causes the display page to clear. On the other hand, to delete a single row on a page, the page is retrieved as stated above, the INSERT button or key on the keyboard 82A is depressed, the appropriate row or column co-ordinates are then keyed in via the keyboard 82A, the SPACE button or key on the keyboard 82A is depressed and then the TRANSMIT button or key is depressed, thus clearing the communication message. However, it may normally be utilized for repetitive type of information, such as the subscriber identifier, so as to minimize the creation time for the message.

Referring now to FIG. 8D, a typical alerts page or alerts list is illustrated. This alerts list, designated LSTA in the example of FIG. 8D, is normally stored at the respective terminal controller 80A, 80B or 80C, by way of example, in response to receipt of alert communication messages designated for that particular terminal controller 80. The last received message is preferably stored in row 3 of the displayable alerts list page with the previously received alerts communication messages being respectively scrolled down one row so that the first or earliest message would appear at the bottom most row of the list which can preferably contain up to 10 displayable alert communication messages. It should be noted that if more than 10 alert communication messages are received prior to display of one of these messages by the recipient, then the earliest received message is lost. In order to avoid this, if desired, the printer 150A, for example, may be enabled so that all incoming alert communication messages will be printed, thereby avoiding the possibility of any of these messages being lost. A recipient subscriber is advised that there is an alert communication message due to the display of a flashing message such as "SEE ALERTS PAGE" on row 14 of the display 82B. When the subscriber sees this message, he may input the alerts page designation, such as LSTA, via the keyboard 82A and thereafter depress the transmit button on keyboard 82A which will then cause display of the alerts page on the screen 82B. Preferably, at the same time that the "SEE ALBERTS PAGE" message comes up on the display 82B, a buzzer on the keyboard 82A will sound, providing an audible alarm signal to the subscriber for a pre-defined period, such as five seconds. The buzzer is self-cancelling after the five second interval; however, line or row. Thus, summarising the above alert communication system of the present invention, such as with respect to its utilization for providing international shipping market alerts, it enables essential market data such as enquiries, fixtures and market reports to be channelled rapidly and accurately to the required destination allowing subscriber contributors to insert items of information into their keystation and make this information, under their own name, available to the shipping market world-wide with the market data or alert communication messages being directed to subscriber recipients at the discretion and under the control of the subscriber contributor. In addition, recipients have access to information from named contributors displayed on the screen 82B at their keystation with general background information such as fixtures and market reports being available on contributed or subscriber originated pages which may be retrieved at any time. Thus, brief but urgent information can be sent to wide audiences in the form of alert communication messages while users may be informed in greater detail through the use of subscriber originated ordinary pages of data thereby enabling a subscriber contributor to rapidly inform the subscriber contributor's own designated variable list of recipients of essential market data rapidly and accurately.