Abstract:
An infrared communication system provides a communication link between a stand-alone electrically controlled lock and a centralized control system. A module comprising a transmitter and a receiver is mounted in fixed position to the door frame. A second module comprising a transmitter and a receiver is mounted to the door.

Description:
This application claims the benefit of U.S. Provisional Application 60/011,263 filed on Feb. 7, 1996. 
    
    
     This invention relates to the field of door security systems. More particularly, this invention relates to an optical communication system for an integrated lock control system. 
     Devices which provide programmable access to individual electrically controlled door locks are well known in the field of door security systems. Door security systems generally employ either centrally controlled door locks or stand-alone door locks. Both types of door locks typically operate by requiring a user to enter a personal access code at an access code reader located at the site of the door. Entry of a valid access code initiates an unlocking sequence for passage by the user through the door. 
     Centrally controlled door locks are typically wired from the door location to a programmable central control console at a remote location. Centrally controlled lock systems generally entail increased installation costs when compared to other door security systems. For centrally controlled lock systems employing electrically controlled mortise and cylindrical locks, wiring is typically installed between the door frame and the door by use of a shielded communication cable at the hinged edge of the door. Lock system reliability can be compromised because communication cables between doors and door frames are susceptible to wear and can be exposed to tampering. Furthermore, for aesthetic reasons, a passage must be provided for the communication cable from the hinged edge through the door to the electrically controlled mortise or cylindrical lock. For solid doors, providing this passage is a relatively time-consuming and expensive requirement. 
     In response to the increased initial expense and other deficiencies of centrally controlled and wired lock systems, less centralized systems which are relatively inexpensive, easy to install and electronically sophisticated have been widely employed. For example, stand-alone electrically controllable locks may be installed at each door location. Such stand-alone systems are typically not wired through the door and are separately powered by on board batteries associated with the lock. Many stand-alone systems are programmable to provide a number of operational options and are capable of compiling usage information or an audit trail. 
     While there are a number of advantages of stand-alone systems, there are also a number of disadvantages. Each stand-alone door lock is individually and independently programmed with valid user access codes. Any audit trail information compiled must be individually and independently downloaded from each lock. Because each door lock is independent, security personnel are required to visit each door location. The individual programming and downloading process for each lock of the security system is inefficient. 
     It may also be desirable to program changes in valid user access codes relatively simultaneously to all locks in the security system so as to preclude inconsistent valid access codes at different doors for a common secured area. Furthermore, in order for the entire security system to remain effective and current, it is desirable to program access code updates as required. Security systems employing independently operable stand-alone locks may therefore prove unwieldy and inefficient for securing larger numbers of doors. 
     SUMMARY OF THE INVENTION 
     Briefly stated, the invention comprises an optical communication system for communicating between a stand-alone electrically controlled lock and a centralized lock control system. 
     In the preferred embodiment of the invention, the optical communication system comprises a network communication module having an infrared network transmitter and an infrared network receiver mounted in a fixed position relative to the door frame. The network communication module is integrated with a remote lock network or lock control console. A corresponding lock communication module having an infrared lock transmitter and infrared lock receiver is mounted to the door. The lock communication module is integrated with the stand-alone lock. The pairs of infrared transmitters and receivers are oriented in a manner such that when the door is in a closed position, the respective transmitters and receivers are in opposing line-of-sight relationship. The opposed pairs of transmitters and receivers provide bi-directional wireless communication between the stand-alone lock and the remote lock control console. This optical communication system employs the opposed pairs of infrared transmitters and receivers to transfer lock commands, access codes and audit trail data between the stand-alone lock and the remote lock control console. The stand-alone lock can therefore be programmed, monitored and accessed from the remote location of the lock control console for audit trail data. 
     The communication system further facilitates networking and the efficient integration of numerous stand-alone locks into a comprehensive lock system. The addition or deletion of user access codes from the entire lock system can be accomplished on a single occasion by the networking function provided by the optical communication system. Furthermore, individual stand-alone locks can be easily and immediately accessed for audit trail data from a central location. 
     An object of the invention is to provide an optical communication system that provides communication between a stand-alone type door lock and a remote lock control console. 
     Another object of the invention is to provide a lock communication system that does not require wire communication lines between a door frame and an associated secured door. 
     A further object of the invention is to provide a lock communication system wherein programming of a stand-alone door lock is accomplished without requiring the presence of security personnel at the door lock site. 
     A still further object of the invention is to provide a lock communication system capable of both centralized programming and audit trail compilation from multiple units of a stand-alone door lock system. 
     Another object of the invention is to provide a lock communication system for the networking of multiple independent stand-alone locks from a remote location. 
     These and other objects of the invention are readily apparent from the specification and the accompanying drawings. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a front schematic view, partially in phantom, of the optical communication system of the invention in combination with an associated stand-alone lock, doorway and central control console; 
     FIG. 2 is a partial block diagram of the optical communication system, lock, doorway and lock control console of FIG. 1; 
     FIG. 3 is a partial schematic electrical diagram of a communication module of the optical communication system of FIG.  1 . 
     FIG. 4 is a detailed block diagram of the optical communication system, lock, doorway and lock control console of FIG. 1; 
     FIG. 5 is a partial cross-sectional view of the optical communication system, doorway and stand alone lock of FIG. 1 taken along the line  5 — 5  thereof; and 
     FIG. 6 is a partial longitudinal view of an alternate installation of the optical communication system of the invention with a doorway and a stand-alone lock. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     With reference to the drawings, wherein like numerals represent like components throughout the figures, a stand-alone electrically controlled door lock is generally designated by the numeral  10 . The stand-alone door lock  10  is mounted to a door  12  and latches to a door frame  14  for controlling access through the door  12 . 
     The stand-alone lock  10  is preferably an electrically controlled mortise lock or cylindrical lock, but can comprise an electrically controlled electromagnetic lock or other electromechanical lock. The stand-alone lock  10  has a lock controller  16  and an electrically controlled lock mechanism  18  such as an electrically controlled latch. The stand-alone lock  10  preferably further has an on-board power source and an access code reader  17 . 
     The access code reader  17  is preferably a numerical touch pad. A lock user enters a personal access code at the access code reader  17  to place the stand-alone lock in an unlocked state. The access code reader  17  may alternatively be a card reader, a contact activatable dataport or other system for receiving an access code. Access codes entered at the access code reader  17  are transmitted by the reader to the lock controller  16 . 
     The lock controller  16  of the stand-alone lock  10  has a microprocessor and an associated on-board memory. The microprocessor compares an access code received from the access code reader  17  to a series of valid access codes stored in the on-board memory. If an appropriate comparison is obtained, the lock controller  16  generates a release signal. The release signal is transmitted by the lock controller  16  to the electrically controlled lock mechanism  18 , thereby placing the stand-alone lock  10  into the unlocked state. 
     The lock controller  16  is programmable for the addition or deletion of valid access codes from the on-board memory. The lock controller  16  is also programmable with lock commands. Additionally, the lock controller  16  preferably compiles and stores an audit trail in the on-board memory. The audit trail may typically include listings of access codes entered at the access code reader  17 , times corresponding to the entry of the access codes and other lock event information. Furthermore, the lock controller  16  is preferably further programmable for initiation of an alarm  15  upon entry of designated access codes and/or invalid access codes. 
     A central control console  30 , preferably a computer, is employed for programming and networking multiple stand-alone locks  10 . Security personnel can program the lock controllers  16  of particular stand-alone locks  10  with lock commands and access codes from the central control console  30 . The lock controllers  16  can be programmed individually or as part of a predetermined set or subset of a network of lock controllers  16 . The central control console  30  can also receive and display audit trail data from a designated lock controller  16 . The central control console  30  may additionally be programmed to receive and display an alarm signal generated by a lock controller  16 . 
     The optical communication system  13  transmits lock commands, access codes, alarm signals and audit trail data between the lock controller  16  of the stand-alone lock  10  and the central control console  30 . The optical communication system  13  comprises a lock communication module  19  and a network communication module  28 . The lock communication module  19  and network communication module  28  preferably have a similar construction to provide reduced component manufacturing costs, modular application of the components, and simplified system maintenance. In the preferred form, each optical communication module  19 ,  28  is manufactured as a single electrical unit for compact and simplified construction (see FIG.  3 ). 
     The lock communication module  19  is wired to and communicates with the lock controller  16 . The network communication module  28  is connected by a communication line  31  to and communicates with the central control console  30 . The lock communication module  19  and network communication module  28  are in opposing line-of-sight positions wherein the lock communication module  19  is mounted to the movable door  12  and the network communication module  28  is mounted in a fixed position relative to the door frame  26 . 
     The lock communication module  19  comprises an infrared lock transmitter  20  and an infrared lock receiver  22  mounted to the door  12 . The infrared lock transmitter  20  and the infrared lock receiver  22  are preferably positioned for transmission and reception through the outside vertical door edge face  24  of the door  12 . The lock transmitter  20  and lock receiver  22  are furthermore preferably located in the same mortise in the door  12  as the latch  18  and other components of the stand-alone lock  10  so as to minimize installation modifications to the door  12 . 
     The network communication module  28  comprises an infrared network transmitter  34  and an infrared network receiver  32 . The network communication module  28  is located in a fixed position relative to the door frame  14 . The network transmitter  34  is positioned in opposing line-of-sight relation to the lock receiver  22 , and the network receiver  32  is positioned in opposing line-of-sight relation to the lock transmitter  20 . For applications wherein the lock communication module  19  is mounted to the door edge face  26 , the corresponding network communication module  28  is mounted to the inside frame edge face  26  of the door frame  14 . (See middle portion of FIG.  5 ). The infrared transmitters  20 ,  34  each employ an infrared LED. 
     The lock communication module  19  and the network communication module  28  can be positioned in several alternate opposing line-of-sight relationships wherein the lock communication module  19  and the network communication module  28  are mounted to the door and affixed relative to the door frame, respectively. With reference to FIG. 5, the lock communication module  19  can be mounted to a face of the door  12  and the network communication module  28  can be affixed to a rabbet  27  in the door frame  26 . (See left portion of FIG. 5.) For stand-alone locks having a lock housing  11 , the lock communication module  19  may be mounted to transmit and receive through the side of the lock housing  11 . Therefore, the network communication module  28  will be mounted in a fixed position adjacent to the door frame  14 . (See right portion of FIG.  5 ). Alternately, the lock communication module  19  may be mounted to transmit and receive through the top or bottom of the lock housing  11 , and the network communication module  28  will be mounted in opposing line-of-sight position on a ceiling  23  or a floor  25 , respectively. (See FIG. 6.) 
     During operation of the optical communication system  13 , data, such as access codes or lock commands, is transmitted as an electrical signal from the central control console  30  to the network communication module  28  (see FIG.  2 ). The electrical signal from the control console  30  is converted into an optical signal by the network communication module  28 , as described below. The optical signal is transmitted by the network communication module  28  to the lock communication module  19 . The lock communication module  19  receives the optical signal, converts the optical signal to an electrical signal and finally transmits the electrical signal to the lock controller  16 . By the reverse communication pathway, data, such as audit trail information, can be transmitted from the lock controller  16  to the central control console  30 . 
     In the preferred embodiment of the optical communication system  13 , the optical signal transferred between the lock communication module  19  and the network communication module  28  is an infrared beam. The transmission and reception of data embodied in the optical signal is accomplished by a standard RS 232 protocol or other protocol. In operation, the optical communication system  13  employs a half duplex code that allows only one transmission direction, either lock controller  16  to control console  30 , or control console  30  to lock controller  16 , to be active at any given time. The transmission and reception of data can occur in either direction from the lock controller  16  to the control console  30  or from the control console  30  to the lock controller  16 . 
     Data communications may originate from the control console  30  or the lock controller. The control console  30  signals the network communication module  28  to begin transmitting data (see FIG.  4 ). The network steering logic  42  of the network communication module  28  triggers thereby enabling the network transmitter  34  and disabling the network receiver  32 . The data is transferred to a network driver  35  and is converted to an optical signal by the network transmitter  34 . The optical signal is then transmitted by the network transmitter  34  to the lock receiver  22  of the lock communication module  19 . The network edge detector  44  starts timing a period which detects the absence of data edges for a period no greater than one data byte transmission length. The lock receiver  22  detects the optical signal, and converts the optical signal to an electrical signal that is then sent to a lock amplifier/comparator  36 . 
     The lock amplifier/comparator  36  amplifies and compares the electrical signal to a known reference value. The lock communication module  19  then triggers the lock steering logic  40  to enable the lock receiver  22  and disable the lock transmitter  20 . The lock edge detector  40  of the lock communication module  19  starts a timing period which detects the absence of data for a period no greater than one data byte transmission length. When data transmission ceases, both the network edge detector  44  and the lock edge detector  38  time out reenabling both of the lock and network transmitters  20 ,  34  and both of the lock and network receivers  22 ,  32 . 
     The lock controller  16  can also transmit audit trail data to the control console  30 . The lock controller  16  will receive a command from the central control panel  30 , via the communication path and in the manner previously disclosed, to begin transmitting audit trail data stored in the on-board memory. The lock steering logic  44  is triggered which enables the lock transmitter  20  and disables the lock receiver  22 . A lock driver  21  receives the audit trail data and transmits an electrical signal of the data to the lock transmitter  20 . The lock transmitter  20  converts the electrical signal to an optical signal and transmits the optical signal to the network receiver  32 . The lock edge detector  38  of the lock communication system starts timing a period which detects the absence of data edges for a period of no greater than one data byte transmission length. The network receiver  32  detects and converts the optical signal to an electrical signal. The network amplifier/comparator  33  amplifies the electrical signal and compares the signal to a known reference value. The network communication module  28  then triggers the network steering logic  42  to enable the network receiver  32  and disable the network transmitter  34 . The network edge detector  44  of the network communication module  28  then starts a timing period which detects the absence of data for a period no greater than one data byte transmission length. When data transmission ceases, both the lock and network edge detectors  38 ,  44  time out, reenabling both of the lock and network transmitters  20 ,  34  and both of the lock and network receivers  22 ,  32 . This two-step, half-duplex process repeats until all data transmission between the lock controller  16  and the control console  30  has been completed. 
     The lock controller may also originate communications to the control console, for example, to indicate that an alarm condition or a low battery condition is detected. Communications with the lock controller  16  can also be initiated at the doorway by use of a local communication port  29 . The local communication port  29  enables communication via the optical communication system  13  between a portable control console, such as a portable computer, and the stand-alone lock  10 . The portable control console may therefore program and receive audit trail data from the lock controller  16 . 
     It should be recognized that the optical communication system  13  of the invention can be employed in a lock system wherein the local communication port  29  receives access codes and transmits those access codes to the lock controller  16  for generating a release signal to the electrically controlled latch  18 . Similarly, the local communication port  29  can receive and transmit access codes to the control console  30 . The control console  30  can then signal the lock controller  16  for lock actuation by use of the optical communication system  13 . A lock system of this construction and operation would only require the optical communication system  13  to operate in a single direction. 
     While a preferred embodiment of the foregoing invention has been set forth for purposes of illustration, the foregoing description should not be deemed a limitation of the invention herein. Accordingly, various modifications, adaptations and alternatives may occur to one skilled in the art without departing from the spirit and the scope of the present invention.