Abstract:
A telephone is controlled using an external contact closure. The telephone includes a contact closure connector. The contact closure connector includes a first wire contact and a second wire contact. Control logic is connected to the first wire contact and the second wire contact. The control logic detects a change in electrical connection between the first wire contact and the second wire contact. Alternatively, the control logic detects a change in electrical connection between multiple pairs of wire contacts. In response to the change in electrical connection, the control logic issues a command to a processor connected to the control logic. The processor, upon receipt of the command issued by the control logic, implements a predetermined telephone function or set of functions.

Description:
BACKGROUND  
         [0001]    1. Field of the Invention  
           [0002]    The present invention concerns telephone systems and pertains particularly to using an external contact closure to control a telephone.  
           [0003]    2. Related Information  
           [0004]    Telephones provide powerful communication links between people. By merely entering a particular sequence of numbers on a keypad, a telephone can be immediately connected with locations throughout the world. While a telephone keypad is currently the standard user interface, there are often interactions with a telephone which would be best served by another type of interface.  
           [0005]    One telephone interface which is increasingly used is an application programmer&#39;s interface (API). A telephone generally implements an application programmer&#39;s interface (API) using an API control port. Typically, however, API control ports are very expensive and require a complex phone configuration/setup and/or complex cabling. Additionally, an external device connected to an API control port has to have sufficient intelligence to interact with the API control port. In general, API is used for true computer telephone integration (CTI) applications which require considerable set-up and programming.  
           [0006]    Many users do not need the complex functions implemented by an API, but could use targeted control for particular circumstances. What is needed is a reliable, simplified means for control of specific telephone features.  
         SUMMARY OF THE INVENTION  
         [0007]    In accordance with the preferred embodiment of the present invention, a telephone is controlled using an external contact closure. The telephone includes a contact closure connector. The contact closure connector includes a first wire contact and a second wire contact. Control logic is connected to the first wire contact and the second wire contact. The control logic detects a change in electrical connection between the first wire contact and the second wire contact. In response to the change in electrical connection, the control logic issues a command to a processor connected to it. The processor, upon receipt of the command issued by the control logic, implements a predetermined telephone function.  
           [0008]    The present invention provides an efficient and low cost implementation for accessory control of a telephone. The implementation is reliable and can be used within an emergency system. Additionally, since the invention can be implemented within a private branch exchange (PBX) phone system, many of which are battery powered, various embodiments of the present invention can maintain functionality even during power outages. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0009]    [0009]FIG. 1 is a simplified block diagram of a telephone system which includes a contact closure accessory device in accordance with a preferred embodiment of the present invention.  
         [0010]    [0010]FIG. 2 is a simplified block diagram of a telephone which includes control logic for detecting closure of contacts in accordance with a preferred embodiment of the present invention.  
         [0011]    [0011]FIG. 3 is a simplified block diagram of a telephone which includes control logic for detecting closure of contacts in accordance with an alternative preferred embodiment of the present invention.  
         [0012]    [0012]FIG. 4 is a flow chart of a method in accordance with the present invention.  
     
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0013]    [0013]FIG. 1 is a simplified block diagram of a telephone system which includes a telephone  11  and a contact closure accessory device  14 . Telephone  11  includes a contact closure connector  12 . Contact closure connector  12  includes two wire contacts. Telephone  11  detects when electrical contact is made between the two wire contacts and/or when electrical contact is broken between the two wire contacts. For example, in one embodiment, telephone  11  performs a predetermined function when even temporary electrical contact is made between the two wire contacts of contact closure connector  12 . In another embodiment, telephone  11  performs a predetermined function when electrical contact is (even temporarily) broken between the two wire contacts of contact closure connector  12 .  
         [0014]    The predetermined function performed by telephone  11  is, for example, simulating the pressing of a function key on a keypad of telephone  11 , dialing a pre-programmed telephone number, going off-hook, or some other telephone function.  
         [0015]    Contact closure accessory device  14  is connected to contact closure connector  12  via a connection line  13 . Connection line  13  consists of, for example, two insulated electrically conductive wires. Each electrically conductive wire is connected to one of the wire contacts of contact closure  12 . Contact closure accessory  14  is, for example, any device which provides for temporary connection or disconnection of the two insulated electrically conductive wires within connection line  13 .  
         [0016]    For example, contact closure accessory device  14  is a button switch which provides for temporary connection of the two insulated electrically conductive wires within connection line  13  when a button is pressed. Such a button switch is designed, for example, to be suitable to be placed in a hospital room for use by a patient to call a nurse. In this case, the predetermined function performed by telephone  11  is, for example, dialing a particular telephone number (or extension) of a central nurse station. Alternatively, the button switch is designed to be suitable to be placed close to a bank teller station for use by the bank teller in an emergency. In this case, the predetermined function performed by telephone  11  is, for example, dialing a particular emergency telephone number (or extension) to alert officials of an emergency situation.  
         [0017]    Alternatively, contact closure accessory device  14  is, for example, a switch wired to a secure door or a secure window. When the secure door or secure window is opened (or closed) contact closure accessory device  14  disconnects (or connects) the two insulated electrically conductive wires within connection line  13 . In this case, the predetermined function performed by telephone  11  upon detecting the disconnection (or connection) is, for example, dialing a particular telephone number (or extension) of a central security station.  
         [0018]    Alternatively, contact closure accessory device  14  is, for example, a fire alarm or a power-fail detector. When the fire alarm or the power-fail detector detects a fire or power failure, contact closure accessory device  14  disconnects (or connects) the two insulated electrically conductive wires within connection line  13 . In this case, the predetermined function performed by telephone  11  upon detecting the disconnection (or connection) is, for example, dialing a particular emergency telephone number (or extension).  
         [0019]    [0019]FIG. 2 is a simplified block diagram of telephone  11 . Telephone  11  includes a phone link interface  22  connected to a phone line  21 . Phone link interface  22  provides communication to a telephone exchange system  10 . Telephone exchange system  10  is, for example, a private branch exchange (PBX) or a central office switch. For example, phone link interface  22  interfaces with telephone exchange system  10  using an analog connection, a digital connection, or an integrated services digital network (ISDN) connection.  
         [0020]    A microprocessor  23  acts to control operations within telephone  11 . Microprocessor  23  communicates with phone link interface via a connection link  25 .  
         [0021]    Control logic  24  monitors a contact closure contact  27  and a contact closure contact  28 . In one embodiment of the present invention, when control logic  24  detects electrical connection between contact closure contact  27  and contact closure contact  28 , control logic  24  passes a command over a control bus  26 . In an alternative embodiment of the present invention, when control logic  24  detects electrical disconnection between contact closure contact  27  and contact closure contact  28 , control logic  24  passes a command over control bus  26 .  
         [0022]    When microprocessor  23  receives the command from control logic  24 , microprocessor  23 , depending upon implementation, either executes the command or forwards the command via phone link interface  22  for execution by telephone exchange system  10 .  
         [0023]    For example, upon control logic  24  detecting electrical connection between contact closure contact  27  and contact closure contact  28 , control logic  24  passes a command over a control bus  26  which indicates that the connection has taken place. In response to this command, microprocessor  23  forwards to telephone exchange system  10  a series of keystrokes which include a telephone number or other code. Alternatively, in response to the command, microprocessor  23  forwards to telephone exchange system  10  one or more feature key keystrokes. The telephone exchange then performs whatever feature is associated with the feature key. Alternatively, in response to the command from control logic  24 , microprocessor  23  performs whatever feature is associated with a feature key.  
         [0024]    [0024]FIG. 3 is a simplified block diagram of an alternative embodiment of telephone  11 . Telephone  11  includes a phone link interface  122  connected to a phone line  121 . Phone link interface  122  provides communication to telephone exchange system  10 . For example, phone link interface  122  interfaces with telephone exchange system  10  using an analog connection, a digital connection, or an integrated services digital network (ISDN) connection. A microprocessor  123  acts to control operations within telephone  11 . Microprocessor  123  communicates with phone link interface via a connection link  125 .  
         [0025]    Control logic  124  monitors a contact closure contact  127  and a contact closure contact  128 . In one embodiment of the present invention, when control logic  124  detects electrical connection between contact closure contact  127  and contact closure contact  128 , control logic  124  passes a command over a control bus  126 . In an alternative embodiment of the present invention, when control logic  124  detects electrical disconnection between contact closure contact  127  and contact closure contact  128 , control logic  124  passes a command over control bus  126 .  
         [0026]    When microprocessor  123  receives a command from control logic  124 , the microprocessor accesses a function associated with the command from a non-volatile memory  130  via a control bus. The microprocessor then executes the function. For example, microprocessor  123  executes the function by forwarding to telephone exchange system  10  a series of keystrokes which form a telephone number. Alternatively, microprocessor  123  can execute the function by forwarding to telephone exchange system  10  one or more feature key keystrokes.  
         [0027]    The advantage of using non-volatile memory  130  is that the function is stored in non-volatile memory and thus is both programmable and yet is not lost when telephone  11  is reset or loses power.  
         [0028]    As illustrated by an alternative access route  132 , the function may be accessed by control logic  124  rather than microprocessor  123 . In this embodiment, control logic  124 , upon connection (or disconnection) of contact closure contacts  127  and  128 , forwards the function to microprocessor  123 . Microprocessor  123  either performs the function or forwards the function, via phone link interface  122 , to telephone exchange system  10 .  
         [0029]    In either embodiment as shown in FIGS. 2 and 3, more than one pair of contacts can be used. Accordingly, more than one function can be implemented. A second pair of contacts is schematically shown in FIG. 4 as contacts  127 A and  128 A. The second pair is shown in dashed lines to indicate that they are optional.  
         [0030]    [0030]FIG. 4 illustrates a method  400  in accordance with the present invention. Control logic within a telephone monitors, at a step  402 , first and second wire contacts to detect changes in electrical connection. If a change is detected, at a step  404 , the control logic issues, at a step  406 , a command to a processor within the telephone. Upon receiving the command, the processor implements, at a step  408 , a predetermined telephone function, as for example, the telephone going off hook or dialing a number.  
         [0031]    Although particular embodiments of the invention have been shown and described, it is understood that various modifications are possible within the spirit and scope of the invention, the scope of which is limited only by the following claims.