Abstract:
A system for providing information about the visual appearance of printed circuit cards in a card rack. A database is maintained at the site of the card rack, which contains data, such as a bit-map, indicating visual appearance of each card. When a remote party wishes to construct a computer display containing a view of a card, the party obtains the appropriate data from the database, and uses it to construct the image.

Description:
BACKGROUND OF THE INVENTION 
     Rack-Mounted Printed Circuit Boards 
     Many electronic systems, such as telephone switching stations, or robotic manufacturing facilities, require extensive electronic circuitry for their operation. Frequently, the electronic circuitry is implemented in the form of numerous, interconnected, printed circuit boards. These printed circuit boards, commonly called “cards” or “packs,” are often mounted in card cages, which are themselves supported by racks. FIG. 1 is a simplified example of a card cage  3 , supported by a rack  6 , and containing cards  9 . 
     The individual cards often contain visual signal indicators, which provide information to technicians. For example, each card  9  of FIG. 1 may be equipped with an LED  12  which acts as a “pilot light,” indicating whether the card is receiving electric power. Some cards  9  may be equipped with switches  13  which control power delivery to the card  9 . As another example of an indicator, each card  9  may be equipped with a second LED  15 , which indicates whether a certain type of fault has occurred in the card. 
     Regarding fault indication, some cards  9  include circuits in pairs, namely, a primary circuit and a back-up circuit (not shown). An LED indicator, such as indicator  15 , provides three pieces of information about the pair, for example: 
     1. If neither circuit has experienced a fault, the LED indicator will display a green color. 
     2. If the primary circuit has experienced a fault, so that the back-up circuit has taken over operation, the LED indicator will display a yellow color. 
     3. If both the primary circuit and the back-up circuit have experienced faults, the LED indicator displays a red color. 
     In addition to cards  9 , in the general case, the card cages  3  can include other equipment. Apparatus  18  illustrates a generic type of additional equipment. This apparatus  18  includes visual indicators, such as meter  21  and an LED bar graph  24 . This apparatus  18  also includes dual-function controls, such as rotary dials  27  and switches  30 . These latter components are termed dual-function, because they perform a control function, as by selecting a switch position in the case of rotary dials  27 , and they also act as visual indicators, by visually indicating the position presently assumed by the switch. This apparatus can also include connectors  28  which connect with various components of the rack  6 . 
     Two specific examples of such additional equipment  18  are (1) a power supply and (2) a testing-and-control center, which provides jacks and test ports which connect with all of the cards, to which test equipment can be connected. 
     Management Systems for Card Cages Shelf View 
     Management systems exist which allow a person, located remotely from the cards themselves, to view an image of the cards, including an image of the visual signal indicators. FIG. 2 is a representation of such an image, called a “shelf view,” which is displayed on a computer monitor  36 . Conceptually, the image resembles a television picture produced by a video camera which is focused on the cards  9  of FIG.  1 . 
     However, the management systems, in general, do not actually use video cameras. Instead, they synthesize the image shown in FIG. 2, from two sources. One source is data which represents the basic visual appearance of the cards  9 , but not of the indicators, such as LED  12 . This data can take several forms. 
     One form is a bit-map, which can be derived from digitizing a photograph of the cards. Another form is a vector-map, which can be produced by a skilled artist who manually sketches the cards, as by using Computer Aided Drafting (CAD) software, or by tracing a photograph of the cards, using the same software. A significant feature of these forms of the image is that they are “static,” since they do not change, as time progresses. 
     Superimposed over the static images is a “dynamic” image, which represents the current state of the signal indicators. In FIG. 2, for example, the image  15 A may be displayed in the color red, thereby indicating the color shown by the actual LED  15  of FIG.  1 . This color red can change with time, as the color of actual LED  15  in FIG. 1 changes. 
     In the more general case, as indicated in FIG. 2, additional visual indicators can be displayed, including switches  13  and  30 , and the positions of rotary dials  27 . In addition, if a particular card is absent, the slot previously occupied by the card is indicated by a greyed-out rectanngle  37 . 
     Use of Shelf View 
     The management system is used to troubleshoot problems occurring in the cards  9 . In a telephone switching station, thousands of cards may be contained in a single building, which is staffed by a single technician. Many such buildings are under control of a central office. 
     When a problem occurs in one of the buildings, an expert, located at the central office, and using the shelf view of FIG. 2, locates faulty cards, and guides the technician through the process of replacing the faulty cards. 
     However, the effectiveness of such management systems depends, in part, upon whether the display  36  in FIG. 2 accurately represents the visual appearance of the card cage of FIG.  1 . For example, a technician may replace a card  9  with another card having a different appearance. For the display  36  of FIG. 2 to reflect this change, data indicative of the visual appearance of the new card must be supplied to the workstation. Otherwise, the shelf view of FIG. 2, seen by the expert located at the central office, will not correspond with the actual card cage seen by the technician, and confusion will result. 
     SUMMARY OF THE INVENTION 
     In one form of the invention, data indicative of the visual appearance of printed circuit cards, which are mounted in a rack, is stored at the site of the rack. Upon request, selected data is transmitted to a remote party. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 illustrates rack-mounted printed circuit cards  9 . 
     FIG. 2 illustrates an image of the equipment of FIG. 1, generated by a workstation (not shown). 
     FIG. 3 illustrates one form of the invention. 
     FIG. 4 illustrates communication links  55 A- 55 C existing between a workstation  52  and racks  6 A- 6 C. 
     FIGS. 5-12 illustrate a sequence of events undertaken in one form of the invention. 
     FIGS. 13 and 14 illustrate alternate embodiments of the invention. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     FIG. 3 illustrates a simplified view of the invention. A database  39  is associated with the card rack  6 . The database  39  can be stored in a control unit, which may take the form of a workstation  42 , or a single-board controller (not shown) installed in a card  9 . The database contains a record  48  for each card  9  and, within each record  48 , three types of information, as indicated by the fields  45 A,  45 B, and  45 C. 
     Field  45 A contains the physical characteristics of the card  9 . The physical characteristics allow computer-generation of the static image described above. The physical characteristics refer to the physical appearance of the card, and not to other physical features, such as physical operation of the electronic circuitry contained within the card. 
     From another point of view, a card  9  can be conceptualized as a 6-sided box. However, the physical appearance represents a view of the single, exposed, side (or face) shown in FIG.  1 . That face includes the visual signal indicators  12  and  15 . 
     When a card is mounted in the cage  3 , the exposed face is the only side of the card visible to an observer standing before the rack  6 . Thus, despite the fact that the card may have six sides, the exposed side is the only side of interest, and is taken to represent the physical appearance of the card. However, if more than one side of a card is of interest, then the static and dynamic images can be modified to include the additional sides. 
     The second field  45 B indicates the card type. “Card type” refers to a description of the function which the card performs, and may take the form of a catalog part number of the card. 
     The third field  45 C indicates the status of the visual indicators contained on the card. These indicators include, most commonly, the states of LEDs  12  and  15  in FIG.  1 . But in the general case, the visual indicators include switch  13 , meter  21 , LED bar graph  24 , and rotary switches  27  in FIG. 1, as well as all other visual indications which are relevant to an operator of the system. 
     It is not strictly necessary that the data of field  45 C be stored within the database  39 . One reason is that such storage is redundant, because field  45 C reflects information already displayed by the indicators, such as LED  15  in FIG.  1 . In a sense, the data is already stored at the indicators, and can be retrieved from them, when needed, as by using data link  49  in FIG.  3 . 
     The invention utilizes the database  39  as follows. A large system contains multiple card racks, at different locations, indicated by the three racks  6 A,  6 B, and  6 C in FIG. 4. A workstation  52  communicates with the controller  42  associated with each rack, as indicated by communication links  55 . A user of the workstation  52  selects one of the racks, such as rack  6 B indicated in FIG. 5, and sends message  60  to its controller  42 B, requesting that the controller  42 B identify itself. As FIG. 6 indicates, the controller  42 B identifies itself by transmitting message  63 . 
     Next, as in FIG. 7, the workstation  42  asks controller  42 B to identify either (a) the cards  9  contained in its rack  6 B (shown in FIG.  5 ), or (b) the cards  9  which are actually operational, as appropriate. In FIG. 8, the controller  42 B identifies these cards. (Four cards, namely A, B, C, and D are indicated, for simplicity, rather than the fourteen cards shown in rack  6 B of FIG. 5.) The cards are identified by their “card type,” taken from fields  45 B in FIG.  3 . 
     The workstation  52  in FIG. 8 then ascertains whether it is in possession of the physical characteristics of all the cards identified by message  70 . Assume that the workstation  52  knows the physical characteristics of all of the cards identified, except card D. When the workstation  52  detects the absence of the physical characteristics of card D, the workstation  52  requests the physical characteristics of card D, as indicated in FIG.  9 . That is, the workstation  52  requests a bit-map, or vector map, as appropriate, which indicates the static appearance of card D. The controller  42 B supplies the physical characteristics, as indicated in FIG.  10 . 
     Next, the workstation  52  requests the current status of the visual indicators of the cards, such as LEDs  12  and  15  in FIG. 1, as indicated in FIG.  11 . The controller  42 B transmits the status data, as indicated in FIG.  12 . This status data is taken from fields  45 C in FIG. 3, and allows the current state of the visual indicators to be replicated. 
     The transmission of FIG. 12 is repeated either (1) periodically by the controller  42 B, (2) in response to periodic requests made by the workstation  52 , as in FIG. 11, (3) whenever a status indicator changes, or (4) in some other way to assure that the workstation  52  is always in possession of the current states of the status indicators. 
     Using the data received through the transmissions just described, the workstation  52  generates an image resembling that of FIG. 2, indicating a view of the cards  9 , and other equipment  18 , if present, together with their status indicators. 
     Significantly, the database  39  in FIG. 3 is located at the site of the rack  6 . Whenever a card  9  is replaced in FIG. 3, the database  39  is updated by a technician, so that the record  48  of that card will thereafter contain accurate data, particularly concerning the physical characteristics of the card. That is, if a new card  9 , having a new appearance, replaces an old card of different appearance, the card&#39;s record in the database  39  is changed accordingly. 
     With this updating of the database  39 , whenever the workstation  52  of FIG. 9 requests the physical characteristics of the cards  9 , up-to-date physical characteristics are supplied, so that the workstation  52  can generate an accurate image, of the type shown in FIG.  2 . 
     Alternate Embodiments 
     FIG. 3 indicates that the database  39  is stored within controller  42 . However, other storage approaches can be undertaken, such as that shown in FIG.  13 . 
     Each card  9  contains memory, indicated by dashed box  80 . The memory  80  contains data corresponding to fields  45 A,  45 B, and  45 C, of FIG. 3, as indicated in FIG.  13 . This memory  80  is made available to controller  42 , also shown in FIG. 3, through bus  83  in FIG.  13 . 
     Each card is equipped with communication circuitry  86 , which can take the form of a standard memory controller. The controller  42  knows the memory addresses, within memory  80 , occupied by each of fields  45 A,  45 B, and  45 C. The controller  42 , when requested, reads the appropriate addresses, by issuing the proper “read” signals to the communication circuitry  86 . 
     In the embodiment of FIG. 13, each card  9  contains its own record within memory  80 , analogous to record  48  in FIG.  3 . When a card is removed, and replaced, the physical characteristics of the replacement card are automatically supplied to the system, by virtue of being present in the replacement card itself. 
     FIG. 14 illustrates another approach to storing the database  39  of FIG.  3 . Controller  42  is given access to a card  89 , which contains connectors  92 . Each connector  92  corresponds, by position, to a respective card  9 , as indicated by dashed arrows  95 . 
     Each connector  92  receives a plug-in memory module  98  which bears card-edge connector fingers  98 A, which mate with the connector  92 . The memory module  98  stores the data of fields  45 A and  45 B in FIG. 13, namely, “physical characteristics” and “card type.” The other type of data, namely, that of field  45 C, indicating the current status of the visual indicators, is read in the usual manner, as from the cards  9  themselves. A technician (not shown) assures that the memory modules  98  are plugged into the proper connectors  92 . 
     In operation, the controller  42  in FIG. 4, when requested by controller  52 , reads the appropriate memory modules  98  in FIG. 14, and delivers the information obtained, in the manner described in connection with FIGS. 5-12. 
     A significant feature of FIGS. 13 and 14 is that the database  39  of FIG. 3 does not require re-programming when a card  9  is changed. Restated, the technician responsible for changing a card  9  is not required to deal with any software involved with the database  39 . 
     FIG. 14 has an advantage over FIG. 13, in the respect that the architecture of the cards  9  need not be changed, in order to implement the approach of FIG.  14 . The controller  42  is only required to be given access to bus  99 , and to be re-programmed appropriately, to read the memory within printed circuits  98 . 
     Additional Embodiment 
     FIG. 10 indicates that the workstation  52  obtains the physical-characteristics-data from controller  42 B. An alternate approach is to provide the workstation  52  with an address where the physical characteristics are located, rather than the physical characteristics themselves. 
     For example, it may be expected that the manufacturers of the cards  9  are the best sources of the physical characteristics. By pre-arrangement, manufacturers may, individually or collectively, maintain an on-line database which contains the physical characteristics of their cards. Such a database would be somewhat analogous to the databooks which manufacturers of integrated circuits (ICs) presently provide for their ICs, which contain engineering drawings showing the physical characteristics of the ICs. 
     The controller  42 B in FIG. 10 may, when requested as in FIG. 9, refer the workstation  52  to this database, or the workstation  52  may be programmed to consult this database directly. In either case, the workstation  52  contacts the database, as by using an INTERNET address, and locates the physical characteristics desired, based on the card type, obtained from workstation  42 B. 
     One advantage of this approach is that the database is maintained by the parties having the best knowledge of the physical characteristics of the cards  9 , namely, the manufacturers. 
     RELATED PATENT 
     U.S. Pat. No. 5,513,171, Ser. No. 280,421, issued Apr. 30, 1996, to Ludwiczak, et al., discusses a network management facility, and is hereby incorporated by reference. 
     Numerous substitutions and modifications can be undertaken without departing from the true spirit and scope of the invention. What is desired to be secured by Letters Patent is the invention as defined in the following claims.