Abstract:
An emergency telephone system has a dual mode, hybrid emergency telephone station connected with a central station through both a digital ethernet connection for digital VOIP communication and through a wire line for analog communication. Circuitry at the dual mode emergency station connects a user terminal with the digital ethernet connection and the wire line. A processor forming a part of the circuitry directs communication through the ethernet connection if operative and through the analog wire connection if the ethernet connection is inoperative.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application is a continuation-in-part of Ser. No. 60/919,462. 
     
    
     BACKGROUND OF THE INVENTION 
       [0002]    Emergency telephone systems typically comprise a number of emergency telephone stations, each with a user terminal and located throughout the area to be served, e.g., a college or corporate campus, parking garage, or the like. The emergency telephone stations are connected with a central station where an attendant provides assistance for a user of the emergency telephone station in an emergency situation. 
       BRIEF SUMMARY OF THE INVENTION 
       [0003]    This invention provides enhancements for an emergency telephone system which improves system reliability and afford novel functions and features which make the system easier to us. 
         [0004]    On feature is that the emergency telephone station has circuitry connecting the user terminal with both digital ethernet and analog wire line connections from the emergency telephone station to the central station and the circuitry includes a processor which directs communication between the user and the central station through the digital ethernet connection if the digital ethernet connection is operative and through the analog wire line if the digital ethernet connection is inoperative. 
         [0005]    Another feature in an emergency telephone system having an emergency telephone station connected with a central station through an ethernet connection for communication using V o IP protocol having discrete packets of digital audio signals, is the method of monitoring stats of the system which comprises exchanging status queries from the central station to the emergency telephone station and responses from the emergency telephone station to the central station during intervals between the discrete packets of digital audio signals. 
         [0006]    A further feature of the emergency communication system is that the circuitry connecting the user terminal with the ethernet includes an ethernet converter or an ethernet switch and an IP compatible device, as a personal computer, is connected with the ethernet converter or ethernet switch. 
         [0007]    Yet another feature of the system is that the circuitry connecting the user terminal with the ethernet includes a signal processor and that a visual display is connected with the signal processor displaying messages for the user at the emergency telephone station. 
         [0008]    Yet a further feature is that the emergency telephone station has circuitry connecting the user terminal with either the ethernet connection or the wire line connection and includes a power source, and the emergency telephone station has a visual display to display an out-of-service message, the visual display being connected with the ethernet connection, the wire line connection, and the power source and is responsive to a loss of connection in the ethernet or wire line connections or an outage of the power source to display the out-of-service message, and a solar cell is connected with and powers the visual display. 
         [0009]    Another feature is that the emergency terminal has both a handset and a loudspeaker for communication with the user and the processor in the emergency station circuitry is responsive to a command from the central station to direct an audio message from the central station either to the handset or the loudspeaker. This insures that the message will reach a user who does not remain at the user terminal. 
         [0010]    A further feature is that the emergency telephone system has a primary central station and at least one secondary central station, and the circuitry which directs messages between the emergency telephone station and a central station includes a processor which directs calls to either the primary central station or the secondary central station, depending on the day and/or the time of day. 
     
    
     
       BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS 
         [0011]      FIG. 1  is a block diagram of an emergency telephone system; 
           [0012]      FIG. 2  is a block diagram of a hybrid emergency telephone station; 
           [0013]      FIG. 3  is a block diagram of an analog emergency telephone stations; 
           [0014]      FIG. 4  is a block diagram of a V o IP emergency telephone station; and 
           [0015]      FIG. 5  is a diagrammatic illustration of an out-of-service display. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0016]    The principal components of an emergency telephone system  10  are illustrated in the block diagram,  FIG. 1 . Two emergency telephone stations  12  are connected with central station  14  through both an ethernet connection  16 , e.g., a category 5 cable, and a wire line  18 . In practice, an emergency telephone system will have many more emergency telephone stations located throughout the facility served. 
         [0017]    The ethernet connection  16  provides two-way, digital communication using V o IP protocol. The wire line connection  18  provides two-way analog communication. As will be explained in more detail below, digital communication through the ethernet connection is preferred. The system switches automatically to the analog wire line connection in the event of a failure of the digital communication. 
         [0018]    Preferably, one or more alternate central stations  20  are provided to serve the system in the event of an equipment failure at central station  14  or during periods of little use as night time hours, weekends, and holidays. Alternate central station  20   a  is shown connected with the emergency phone stations  12  through a connection to central station  14 . Alternatively, alternate central station  20   b  is connected directly with each of the emergency telephone stations  12  through an ethernet connection  16  and a wire line connection  18 . 
         [0019]    The emergency telephone station circuitry is shown in block form in  FIG. 2 . At user terminal  22 , handset  26  enables a user to carry on two-way voice communication with an attendant at central station  14 . Alternatively, microphone  28  and loudspeaker  30  may be used. Loudspeaker may also be used by the attendant at the central station to broadcast a message to anyone in the vicinity of the emergency station. 
         [0020]    Ethernet connection  16  to the central station is connected with the emergency station circuitry through isolation transformer or integrated ethernet switch  38 . Wire line  18  is connected with the emergency station circuitry through two-way analog to digital (A/D) and digital to analog (D/A) converter  40 . 
         [0021]    The emergency telephone is controlled by processor  42  with memory  44  which has programed instructions and also receives instructions from central station  14 . Block  46  provides timing for processor  42  and other components of the emergency telephone station and indicates the time of day and date where that information is needed. 
         [0022]    Audio CODEC  52  is connected with handset  26 , microphone  28 , and speaker  30 , and through interface I2S  53  with the audio processor  54  to code and decode audio signals, converting analog signals to 16-bit digital signals and vice versa. Audio processor  54 , with memory  56 , is connected through Host Port Interface (HPI)  55  with processor  42 . 
         [0023]    Ethernet converter  62  is connected between isolation transformer  38  and, through Media Independent Interface (MII)  63 , with processor  42 . MII  63  transfers data using 4-bit nibbles in each direction to and from processor  42 . 
         [0024]    Power (+V) for the emergency telephone station circuitry is provided by power supplies  64   a ,  64   b . The input power may be from an external source, e.g., 110V AC, or from power delivered over the ethernet  16  or the wire line  18 . If the station is operating on power from the ethernet and the wire line and one of them fails, operation will continue with power from the other. 
         [0025]    A user at the user terminal  22  initiates an emergency call with a voice message from handset  26  or microphone  28 . The analog signal is coded at audio CODEC  52  and connected with audio processor  54 . For ethernet communication, the audio processor signal is connected through processor  42  with ethernet converter  62  and isolation transformer  38  to ethernet  16  and thus to central station  14 . A responsive voice message follows the reverse path. 
         [0026]    If the ethernet connection is inoperative, processor  42  directs the emergency message from audio processor  54  through Pulse Code Modulation (PCM) interface  65 , a capacitive isolation link, to converter  40  and to the wire line  18 . Similarly, a responsive message follows the reverse path. Thus, the system continues to operate in the absence of the ethernet connection. 
         [0027]    With the system operating over the ethernet connection, system status checks can be conducted while an emergency call is in progress. In accordance with the V o IP protocol, audio signals are represented by packets of digital signals. Status queries and responses are transmitted over the ethernet connection during intervals between the packets of audio signals. Thus, the system can conduct status checks at any time without interrupting an emergency call. It is not necessary to delay either a status check or an emergency call because the system is already in use. 
         [0028]    An ethernet protocol (IP) device can be added to the system by connection to ethernet switch  38  without requiring an external switch or an additional ethernet line. For example, an IP video camera  78  scanning the area of the emergency telephone station sends the video signal through ethernet switch  38  and ethernet converter  62  to the central station processor  42  and hence to the central station  14  over the ethernet connection or. 
         [0029]    A liquid crystal (LC) display  72  at the user terminal  22  is connected with processor  42  and displays messages for a user of the emergency telephone system. The messages may, for example, indicate the status of an emergency call as —CALL PLACED— or a message from an attendant at the central station  14 , for example, —HELP IS COMING—. 
         [0030]    The attendant at the central station, through instructions sent to processor  42 , controls amplifier  32  for loudspeaker  30  and amplifier  34  for microphone  28 . If, for example, a warning message is to go to all in the vicinity of the emergency telephone station, the message is directed to loudspeaker  30  instead of handset  26 , and sufficient volume is provided to cover the desired area adjacent the emergency station. Moreover, if a message is needed for all people near several or all of the emergency telephone stations in the system, it can be directed by the operator at the central station to the loudspeakers in multiple emergency telephone stations. 
         [0031]    A microphone  80  senses ambient noise at user terminal  22  and through an amplifier in audio CODEC  52  adjusts the volume of the audio signal to handset  26 . 
         [0032]    The processor  42  in the emergency station, under control of clock  46  or a processor at central station  14  under control of an attendant or a memory directs an emergency call to an alternate central station  20 , if appropriate. 
         [0033]    Keypad  70  connected with processor  42  enables a user at the emergency telephone station to touch dial a telephone other than the central station in an appropriate situation; or a number entered on keypad  70  may, if desired, be displayed at LCD  72 . 
         [0034]    When an emergency telephone station  12  is inoperative, it is important that this information be communicated to a prospective user. A liquid crystal display (LCD)  86 ,  FIG. 5 , is powered by an independent power supply, as a solar cell  88 . In the event of a loss of connection in both the ethernet  90  and wire line  92 , or a power outage  94 , the OUT OF SERVICE display is actuated through and gate  96  and or gate  98 . 
         [0035]    Processor  42  operates auxiliary switches  76  under control of the attendant at the central station to turn on or off lights, alarms or other auxiliary equipment at the emergency telephone station. 
         [0036]    The circuitry components for the emergency station are typically mounted on a printed circuit board. The same board can be used in the manufacture of circuit boards for emergency telephone systems using only an ethernet connection or a wire line connection.  FIG. 3  illustrates the circuit for wire line operation.  FIG. 4  illustrates the circuit for ethernet operation. The saving in manufacturing cost makes the provision of multiple systems more economical.